Help with Fermwrap & Fridge using 2 single stage Rancos

[scruffymmh]

I just acquired a fridge for the garage, which I anticipate will be varying between 45 and 80 for the next month or so. So, I'll need heating and cooling for the single 6 gallon carboy i will put in there. I already have a fermwrap and two single stage Ranco ETC111000 digital temp controllers. I have a stopper & thermowell, but obviously can have only one probe in the thermowell. I should probably keep the cooling controller's probe in the beer since the garage will likely be above ferm temp most of the time.

Where should I keep the fermwrap probe? Stuck on side of carboy using bubble wrap? It's not a submersible probe (at least, I don't think it is - it's the standard probe included with unwired ETC111000), so having that probe in a water bath in the fridge isn't an option. Any other suggestions, or do you think bubble-wrap the fermwrap probe to the side of the carboy is the best option? One potential hangup is that the option can't involve me monitoring it often (e.g. switch fermwrap probe into the thermowell at night when it gets cold, then switch back to fridge probe in thermowell in the AM before it warms up) because the garage & fridge aren't at my house.

 

[Keith_Mahoney]

Why do you even need the fermwrap and the additional Ranco if you are using the fridge? The fridge will turn on and off at the appropriate times in order to keep your beer the correct temp.

How cold are you talking about the garage getting at night? the beer fermenting will produce some heat itself and the fridge is insulated so at night it will stay warm inside and keep the cold of the night out. Just like the fridge in you house stays cold inside but not cold outside on it's panels.

 

[scruffymmh]

Thanks for the reply. I guess I'm assuming that if temps at night get to about 40-45, that the fridge, although insulated, will get cold inside too, although not a cold and not as fast. The difference between a fridge inside and a fridge in the garage is that the Fridge inside is always surrounded by room temp, with the compressor continually keeping it cool.

I guess what it comes down to is whether someone out there can tell me for sure that a fridge is generally well-enough insulated to keep the beer at or above about 63 when the temps at night reach 45 or so, and during the day are about 70-75.

 

[Keith_Mahoney]

Well if no one else chimes in with some information you could just experiment yourself. I would take a better bottle I have with a ferm strip on it and fill it it with water. Put it in the fridge with the Ranco probe in it set to your desired temp and run it for a day. Early the next morning get up when it's still cold out and go check the temp on the fermentor.

Just remember that fermenting wort will stay warmer than water.

 

[jfowler1]

Why do you even need the fermwrap and the additional Ranco if you are using the fridge? The fridge will turn on and off at the appropriate times in order to keep your beer the correct temp.

I am going to go in the exact opposite direction.

If you have the fermwrap, thermowell, and a controller, why worry about regulating the fridge? I mean, you want to control the temp of the wort, not the air, right? You are not fermenting the air, you are fermenting the wort. Everyone knows that ambient temp is a pretty crappy gauge of wort temperature. Be it a temp controlled fridge, a cool closet, or a ice bath, ambient is still not representive of wort temp. Those methods help keep things from swinging out of control, but you can't rely on them to nail a temperature.

I am about 2 hours south of Albany, but for government work, we have a similar enough climate - if this works for me, it will work for you.

I use a minifridge, and I can just close my better bottles inside of it. I run the fridge as normal, on a medium cold setting. To be clear, the fridge is on all the time - no controller. I plug the fermwrap into a Johnson Controller, flip it to heat, set a 1 degree allowance, and drop the probe into the carboy cap thermowell. I just close the wires in the door and the weather stripping is still able to make a nice seal. I would say the ambient temp of the fridge is somewhere in the 45-50 degree F range (I say this because I have done lagers in my fridge and I easily had the fermentation temp at 50F). The fermwrap has no trouble heating the wort to whatever temp I ask of it. I can do ales at 67, a Cal common at 62, and as mentioned, a lager at 50. I am trying to be clear as possible, so forgive the repeat, but the fridge temp is constant and uninterrupted. It is the same 45F for every one of these beers.

I strongly advise this method for a few reasons. First, and most importantly, (as stated) you want to control the wort, not the air. By keeping the carboy in a constantly cool environment, and warming the wort up to desired temps, you are assured that the temperature the probe is reading is reflectiing the fermentation conditions. By controlling fermentation this way, you can really learn your yeast's happy zone. You will be amazed how much a beer can change when you ferment a couple degrees warmer or colder. Batches will be much more repeatable, and surprises will be few and far between, if you can repeat a scheduled fermentation program. Second, I feel it is a lot less stressful on the appliance. Personally, I do not like the idea of cycling my fridge on and off. I think it is just happier to run as designed. Having the little fermwrap turn on and off is not nearly as many moving parts. Finally, you still will have a working fridge. I still use my fridge's freezer compartment to store hops, and use a little pocket in the door to store my yeast. You can't do that if you turn the fridge on and off to try to maintain an ambient temp. I understand that most people control the fridge, I just don't understand why. If they already have the equipment, why won't they go a step further and control the wort?

Finally, you mentioned bubblewrapping the probe to the side. I suppose if you take my advice and just use one controller to heat the wort and let the fridge temps ride, the problem is moot - you will be using the thermowell to measure the wort. If not, and you really want to cycle your fridge on and off and you need to attach the probe to the side of the carboy - use caution, and lots of extra tape. I used this tape-to-side method for a while, but one time the probe fell off and the fermwrap ran uncontrolled. Fermentation hit upwards of 98 degrees (this was pre-fridge, on the garage floor, in the middle of winter - don't tell me those things do not have enough power to heat wort as desired). I was pissed, but the worms were happy. On the spot I ordered the carboy cap thermowell.

Joe

 

[scruffymmh]

Thanks for the lengthy and helpful advice. That's an option I didn't consider. Assuming target ferm temp at 64, I could set fridge at the temperature setting (via fridge's own thermostat or by my second ranco using ambient temp of fridge) that will keep it down to about 62, then set fermwrap at 64 with one degree differential.

Your point about setting fridge thermostat lower (45-50) is well-taken. I've heard of people doing multiple beers at diff temps in same fridge. Do you have experience this? For example set fridge at 50 and carboy1 ferments there, then carboy 2 ferments at 61 using a fermwrap and controller, and carboy 3 ferments at 67 using another fermwrap and another controller. I'd imagine insulating the carboys from each other is helpful - is it required?

 

[jfowler1]

Well, I can only fit one better bottle at a time (it is a dorm fridge), but sure, you could keep the temperature of the fridge low and ferment multiple beers at 2 different temps, but you will need to be employing thermowells and fermwraps for each carboy.

I know this bucks convention, but I would really advise against trying to regulate your fridge just below fermentation temp. I still say just let it ride at 45. Personally, I feel you need the air quite cold to keep the wort from warming up too much from fermentation. People put carboys in 60F degree closets, and when things get going, the wort can hit close to 70F. If you are trying to thread the needle with ambient temp, you may not be providing enough refridgeration to keep the wort from exceeding the temperature you set for your fermwrap. You have a fridge that can get colder than a closet - why short change yourself?

To explain, lets accept that wort can get as high as 8-10 degrees above ambient during fermentation. This was my experience when I used to ferment on a 60 degree basement floor with no temp control. I'd pitch, things would start at 60, raise to 68 during fermentation, and as soon as fermentation stalled, it would drop back down to 60. Beers were always underattenuated and green tasting. Using that example, if you set your fridge for 62, and set your heater for 66 (for an ale), if the fermentation temp was able to raise 8 degrees over ambient, it would shoot to 70F (4 degrees hotter than you wanted). Fermentation will slow down, and it will fall back to the 66 you wanted, but you already had a big spike. Spikes = unwanted esters. On the other hand, please look at my schedule for a 66F ale. I leave/set the fridge at 45. I set the controller for 62, and pitch when it reads 62. 12 hours later, I raise the controller two degrees to 64. After 24 hours at 64, I raise the controller to 66, where it remains for the duration of the program. Yes, I am artificially keeping the wort temp 20F above ambient, but it is right where I want it to be. What difference does it make if the heat of fermentation has the wort at 66, or if the heater is keeping the wort at 66?

66F=66F

The other nice thing is that even once fermentation slows, and where typically (in a closet/basement/bathtub) the wort temp would fall back to ambient, I can maintain the temp at 66 with the heater. For a beer where I desire a super clean profile, like an American Pale ale, this works great and allows time for the beer to condition. If I was making an English Bitter (where it is becoming popular to cool temps back down as fermentation slows to preserve esters) I can turn the controller back down a couple degrees at a time and condition slightly cooler than at fermentation temps.

So, if you only wanted to do one fermentation at a time, and had a second controller, I really can't stop you from using it to also regulate your fridge - I just don't see it as neccessary. You are talking about 5 gallons of wort. Once it is sitting at 66F, it will take a long time for it to drop in temperature. It is a lot of warm liquid mass as compared to a small amount of cool air space. I understand that it is a little hard for people to believe that the fermwrap works great even in an environment as cool as 45 - trust me, it works. But if you wanted my advice; if you already had two controllers, and had the space to do multiple beers (which I don't) I would still leave the fridge at 45, and just buy a second fermwrap and thermowell. You could try to warm one beer up to your desired temp, and let the other one fly at fridge temps, but why? It is the same problem I initially mentioned - ambient is a crappy measure of fermentation temps. One beer will be perfectly controlled, the other is like a shot in the dark.

So if you have the space, and two controllers, I am a little jealous. But I won't let my jealousy get in the way of good advice. Fridge set at 45, and each carboy gets its own fermwrap and thermowell. If you are going to do it, do it!

Couple your new fermentation chamber with great sanitation, proper yeast starters and pitch rates, and an O2 kit (my newest kick) and I promise you - you will never be on this board complaining about strange esters, under attenuated beer, or possible infections again. I promise you will be making some killer beer.

Good luck,
Joe

 

[scruffymmh]

Thank you Joe. I will give what you suggest a try -> fridge at about 45-50 and fermwrap at desired temp. If every works smoothly with my setup I'll prob make another fermwrap so i can have 2 going at once. Thank you for the help.

 

[jfowler1]

No problem. My "advice fee" is one growler of the K.A.B. from the Albany Pump Station.

Good Luck,
Joe

 

[scruffymmh]

How about honorable mention as the purveyor of the fermentation technique, should i brew a brown that beats KAB in a competition, plus a complimentary growler of that brew?

 

[jfowler1]

It's a deal.

 

[jfowler1]

Just wanted to quickly revisit.

I brewed a Cal Common on Sunday. I pitched at 58, brought it up to 60 the next morning, and the following morning brought it to its final temp of 62. It will remain at 62 for the next 3.5 weeks.

I snapped a couple picks so you can see the carboy in the fridge, how I set up the heater, and how the probe is reading a wort fermentation temp of 61F (that's what you call fermentation control - I'd like to see a closet dial in a temp like that). The things you can't see are that it is set to a 1 degree allowance (so it will kick on when it hits 60, and turn off as soon as it hits 62) and that it has been wired to heat (because factory setting is to cool).

Enjoy,
Joe

EDIT- Look closely and you can see the ice in the freezer compartment, and you will see that the light is not on on the controller (so the heater isn't even firing). This proves my point that you can leave the fridge in normal working order and it will not be a struggle for the wort to stay in its desired range.

 

[scruffymmh]

Thanks for the update. I'll indeed be using that configuration when I setup the fridge on Saturday. It's a full size fridge that I'm using, so more cold air to impact my fermentin beer, so perhaps more cycles of my fermwrap, but we'll see how it works.

On a side note, I got a better bottle at Christmas and haven't used it yet. Thinking of using it next time I brew. Did you need to wash/soak/etc yours to remove any plastic Taste that a new better bottle would
Impart? Or are they good to go off the shelf?

 

[jfowler1]

Wow - good question about the better bottles.

Honestly, I used one from my first batch, but those first few beers had so many flaws that the potential for me taste an off-flavor contributed by the BB were the least of my concerns.

If I had to take a guess, I would say - don't sweat it. I am a strong believer in the combination of PBW and Star-san. If I had to offer some advice on prepping the new BB, I say just soak it in Warm PBW, rince with warm water, and hit it with Star-san (and follow that procedure for every future brew).

These BB's are made from a pretty inert material. I even find that from beer to beer, once cleaned, I can not pick up characteristics from previous batches (ie - hop aroma, yeast smells, or any specialty grain).

The only other word of warning is that after use, just fill them to the brim with an appropriate concentration of warm PBW (or whatever cleanser you are using). Over an hour or so, the cleanser will do a great job of breaking up the organic material left behind by fermentation. This is pretty much common knowledge, but under no circumstances should you use a carboy brush on a better bottle - you will scratch the hell out of it.

Joe

 

[scruffymmh]

I've read a lot of posts that recommend that same method of cleaning the bottle. I'll use that to prepare the bottle for the first brew. Cost-benefit favors that approach. I plan to use that Oxiclean Green instead of PBW, but I have starsan that I'll use after cleaning. Thanks again for the assistance.

 

[scruffymmh]

I use a minifridge, and I can just close my better bottles inside of it. I run the fridge as normal, on a medium cold setting. To be clear, the fridge is on all the time - no controller. I plug the fermwrap into a Johnson Controller, flip it to heat, set a 1 degree allowance, and drop the probe into the carboy cap thermowell. I just close the wires in the door and the weather stripping is still able to make a nice seal. I would say the ambient temp of the fridge is somewhere in the 45-50 degree F range (I say this because I have done lagers in my fridge and I easily had the fermentation temp at 50F). The fermwrap has no trouble heating the wort to whatever temp I ask of it. I can do ales at 67, a Cal common at 62, and as mentioned, a lager at 50. I am trying to be clear as possible, so forgive the repeat, but the fridge temp is constant and uninterrupted. It is the same 45F for every one of these beers.

I set up my fridge yesterday and it looks like the warmest setting on freezer and fridge still keeps the fridge really cold - like 42F. It was 42.3 tonight when i checked, and my wireless digital thermometer in the fridge, which tracks max/min, said the minimum was 35.8 at one point during the past 24 hours. So it looks like the fridge really fluctuates and is generally pretty cold. I'm going to ferment at 66-67 next weekend and now I'm wondering whether I need to use a temp controller on the fridge to keep it more like 50 in there. What do you think about the fermwrap being able to bring my better bottle up to 67F if i didn't use a temp controller on my fridge and the fridge's inside air was about 40?

 

[jfowler1]

This may have been said already, but if you are not brewing until next weekend, and already have all the equipment, do a test run.

Fill the carboy with 5/5.5 gallons of water, let the friedge run as is, and set your controller to heat. See if you can maintain your "fermentation temp" on a carboy full of water. It is probably a smart idea to try your setup out anyway instead of experimenting on the batch of beer.

I've got a feeling it will work fine, but if not, you will know to regulate the fridge come this weekend. At best, it saves a batch of beer. At worse, it will give you peace of mind.

Joe

 

[scruffymmh]

I'll give that a test run just to be sure. Id like to avoid temp controlling the fridge but I also don't want to be running my fermwrap constantly.

Its tough to monitor b/c the fridge is 20 mins from my house, but I guess the tough part is right now - learning my system - and it will get easier once I know its capabilities.

 

[jfowler1]

You've stirred up my own curiosity. I have probe thermometer that I use in the kitchen. When I get home tonight, I'll throw it in the fridge and get back to you. It will give you a better gauge.

Joe

 

[scruffymmh]

Awesome. Yeah I remember you saying you think your fridge hovers around 45-50 but it sounded like you weren't too sure. I've read fermwrap can boost 15-20 degrees from ambient, and I've been able to ferment at 67F in a 20F garage when I kept the carboy insulated. I just worry that the 25F diff might be hard for me to hold after high krausen. I could probably figure a way to insulate the carboy in the fridge but then it's a tradeoff because it will take fridge longer to cool the beer if fermentation takes off.

I'll put the better bottle in the fridge with fermwrap and i wont insulate it. Then ill test if I can do 67. I'll report my results in case anyone else out there is interested.

 

[jfowler1]

I threw a probe thermometer in the fridge last night. I checked it this morning, and the fridge temp was 48F, and the beer temp was 61. That is only a 12 degree difference, but a Cal Common is not what I typically brew. Generally, I ferment my ales at 67 (using the same fridge setting) so that would be closer to a 20 degree difference.

The fridge has a dial on it from 1-6 (1 being the warmest, 6 being the coldest). I have it set for "2". When I made my Oktoberfest last fall, I decided to cold crash without the heater and I froze half of the beer, so I know that I can get the temps pretty cold.

So from my little experiment, if your fridge is hitting the mid 30's, I do not want to say for sure that the fermwrap would be able to handle +35 degrees, so I am going to backpedal a bit and maybe suggest using one controller to keep the fridge between 45-50F, and use the other controller with a fermwrap and thermowell.

I am not going to say it won't work at 35F, but I can't say for sure that it will. I might crank the fridge a little colder (since I already have everything set up) and follow up one more time.

Joe

 

[scruffymmh]

Thanks for the update Joe. I will run a test overnight to see how the fermwrap does.

It would be easy for me to temp control the fridge at about 47 and then temp control the fermwrap at ferm temp. This seems to be what a lot of people do. my concern would be that the fridge can't keep up with the ramp in temp when fermentation takes off. I'd need to let the heat from ferm bleed out to the fridge temp probe to kick on the fridge. But, it sounds like keeping the fridge at 20F below target ferm will help ensure that fridge temp will dominate the swings in ferm temp.

 

[jfowler1]

So I cranked my fridge last night, turning the dial from "2" to "4". I believe you said your fridge goes to 11 (at least - I think I heard that somewhere).

I got the thermometer to read 43, while the wort temp was still held at 61/62. I felt I was at that point where the needle passes the E, so I bailed out before I found the temp that the fermwrap couldn't keep up anymore. After all, I am all for experiment, but I didn't want to screw up the batch.

The other thing I thought a bit about this morning is that I should probably get a reading in the empty fridge after I take the heated carboy out. Unless I am completely off base, a "2" on the dial could have a colder set temperature than the 47 degrees it currently registers. To explain, maybe 47 is where the ambient temp in the fridge averages out to when you consider that the fridge may actually be having a hard time keeping up with a heated carboy. The carboy probably takes up 75-80% of the space in the fridge, and it is constantly being regulated at 62F.

Lets say the fridge in my kitchen maintains 38F or so. The food inside does not have a heat source, so everything just sits around 38F. In the case of the "fermentation chamber", I have a huge heat source that never hits ambient. So perhaps the fridge keep the carboy from getting too hot, while the carboy keeps the fridge from getting too cold.

Have you conducted your own experiment with water yet?

Joe

 

[scruffymmh]

Thanks for doing some experimenting and sharing. I have not yet. Since the fridge is not at my house, I have limited opportunity to get there for now. I am going there tonight and might set up the BB then. In the event that the fermwrap can't keep up with the fridge, the fermwrap would be continually on, and I'm worried about that b/c my next opportunity to get to my parents basement would be thurs night, 24 hours later if I started it tonight. Plus I'll have no idea about the cycling of the fridge and fermwrap during that time b/c I won't be there. So that's what has me worried now about doing the experiment at this time. So, I'm still contemplating. If it turns out that they would be competing for the full 24 hrs, but that it isnt a big deal for that period of time, then I'd be more inclined to just do it, but i don't have the knowledge to know whether that stress would be too much for the components.

I understand your point about the thermal mass of the beer being greater than the airspace in the fridge. In my case it's a full size fridge so I think I'd be worried about the fridge temps being too dominant over the fermwrap, given the Amt of airspace. And i see your point about not wanting to push the envelope now on your batch.

I will try to do an experiment tonight or sometime before this weekend if I can arrange to somehow monitor the setup and pull the kill switch on it before something goes awry. In any case, I will definitely conduct the experiment - if not this week then in the coming weeks, because I know it's something we are both interested in.

If I can't experiment now, I'll just temp control the fridge at 47 and temp control (via thermowell) the fermwrap.

Also, the temp setting on both the fridge and the freezer go from 1-9 with 9 being warmest. I'll have my max/min on the temp readings reset today and check tonight what the max mins were for the day to double check what my setting at 9 actually produces for fridge temp.

 

[jfowler1]

Also, the temp setting on both the fridge and the freezer go from 1-9 with 9 being warmest. I'll have my max/min on the temp readings reset today and check tonight what the max mins were for the day to double check what my setting at 9 actually produces for fridge temp.

The "turn the dial to 11" things was a bad Spinal Tap reference. The puns are getting bad. I blame my in-laws.

I look forward to hearing about your results, but don't go pushing things with a live beer. Some people are from the "you can't hurt beer" camp. I am not one of those people. When you are at this stage of such precise control, you will quickly see for yourself what a difference a degree or two makes. It is a blessing and a curse.

I will be doing some water tests when I am done with the Cal Common, so I can follow up with that in a few weeks. In the meantime, good luck with your new system.

Joe

 

[Catt22]

This whole thread makes no sense to me. What I don't understand is why you would want to both heat and cool at the same time when one or the other will normally suffice. Am I missing something?

 

[scruffymmh]

Beer is volatile in terms of temperature during fermentation. If fermentation takes off, the temp will ramp up quite quickly. The only way to counteract this would be to cool it off. However, there is no guarantee that the fridge will cool the beer quick enough to counteract this takeoff. By the time the fridge cools the middle of your fermenting beer down to your target temp (assuming you are measuring with thermowell), the beer may have been fermenting for many hours at a temp well-above your target.

One solution is to keep the fridge extra cool so that the fridge ambient temp can more quickly counteract this sudden ramp in temperature cause by takeoff of fermentation. However, because the ramp up in temp from fermentation is not easily quantifiable in terms of when and how intense, we don't know how to regulate the fridge ambient temp exactly so that we retain target fermentation temp. So, we set the fridge extra cold. This means we need to counteract this cold air to the extent that the target temp is maintained. What results is a heat source in constant competition with the cold source. But, that doesnt mean that one is always on or that both are always on. It takes time for the beer temp to swing once it reaches target temp.

This thread is about finding out how cold you can set your cold source while maintaining the ability of your heatsource to overcome the cold source without overworking your equipment. In my case, my cold source is quite cold unless I temp control it. I'm trying to see if my heat source can overcome this without working too hard.

 

[jfowler1]

This whole thread makes no sense to me. What I don't understand is why you would want to both heat and cool at the same time when one or the other will normally suffice. Am I missing something?

That is a good question. The answer is pretty simple really; "one or the other" will generally not suffice (with an emphasis on "generally"). You also have to consider what "suffice" means.

To start, define fermentation control. If we do not have the same definition, it is not even worth discussing. For me, fermentation control means keeping the yeast working in a wort temperature that I dictate. For someone else, fermentation control is a carboy in a fridge. For another brewer, it may be a light bulb in an insulated box.

Think about those three scenarios, they are all technically "temperature control", but only one of them is actually dictating the wort temp, because the other two are only controlling the environment outside the wort.

As a brewer, which should you be concerned about?

Lets look at the four scenarios that all fall under the guise of temp control.
1) A combination of cooling the air and heating the wort
2) Only controlled cooling of the air
3) Only controlled heating of the air
4) An semi-controlled environment that falls in the working temperature range for the yeast.

 

[jfowler1]

1) A combination of cooling the air and heating the wort
By maintaining an ambient (air) temp at less than (let's use) 12-15F of your desired ferm temp, you will have enough of a differential to keep your wort temperature from running out of control as yeast activity increases. Anyone who has fermented in a bath tub/ basment/closet can confirm that they pitch at one temp, things rev up to as much as 10 degrees above ambient, and then once fermentation slows, temps fall back down to ambient. IMO, that is a really poorly controlled fermentation cycle. How can you possibly say you have any control of your yeast when temps are swinging up and down? At that point, the yeast is running the show, not the brewer. Think again about the combination of cooler than fermentation ambient temp coupled with controlled heating of the wort. In my typical example, I will make an American Amber Ale. I want a clean, fully attenuated beer. My goal fermentation temperature for any American Style Ale is 65F using WLP007. Right before I am at the point where I want to pitch, I will have my un-pitched carboy in the fridge (which because of experimentation we now know is at 48F) and wrapped with my fermwrap, which is attached to a Johnson Controller with the probe placed in a carboy cap thermowell. See earlier pictures if that sounds complicated. At this point, the controller is set for 61 (because I believe in pitching cool, allowing for some assimilation, and then bringing wort up to fermentation temps in a controlled manner). As soon as I read the wort temp at 61, I pitch. In the spring, this is as soon as I am done chilling. In the summer it can take an hour or two. But either way, I am pitching this beer at 61. 12 hours after pitching, I crank the wort temp to 63. 24 hours after that, I crank the controller to maintain a temp of 65F with a 1 degree allowance, where it remains for fermentation and conditioning (2,3,4 weeks - whatever you do).

A few things will happen here. Around day 3, when I am at peak krausen, the heater is doing very little work to keep the temp at 65. The yeast are doing the bulk of the job there and keeping themselves warm and happy. Likewise, while the yeast are doing such a great job at keeping temperature high, the fridge is doing a great job of pulling in the reigns so that temps can not get out of control. There was an earlier post made about setting the fridge for 60 and the fermwrap/thermowell for 67, but I didn't think that left enough cooling capacity in the fridge to keep the fermenting wort from ramping past the desired 67 set point (if you follow the 10F over ambient rule). Around day 5, things slow down, and without the heater, the temps will begin to fall closer to ambient (in my extreme case, fridge temp). This would result in the yeast falling out of solution and not finishing their job of cleaning up bi-products. By using the heater to keep temps artificially higher, I keep the yeast active and working. Someone making an English Ale may see that lack of "cleaning things up" as desirable, but it would be inappropriate in my American Ale. The combination of heating and cooling allows me to control the yeast's actual environment (not just the ambient air) every step of the way. Back to that English Ale example, if I want to preserve esters and keep them from being cleaned up too much over a long conditioning period, I just start turning the controller back down as activity slows, but again, I do it at my discression, rather than letting the yeast choose for themselves when they want to stop working.

2). Only controlling the air by cooling. To me, this is a second best option (and what people think of when they hear "fermentation control"). This would be most likely a fridge/freezer hooked up to a temp controller, or something like the SOFC. You are conciously keeping the air temp where you want the wort to be. As many posts show, that is not an easy thing to do. The temp of the air is not changed (up or down) at the same rate as the wort. You have two things in motion here, but they are operating at different speeds, and at often times, in different directions. Consider this - you want to ferment an ale at 65. So you set your fridge at 65. If you control the air, how is that any different than the scenario I discussed earlier about putting the carboy in a bathtub in a 65 degree room, while the fermentation picks up and the wort temp shoots well above 65. On the other hand, if you put the probe in the wort, and set the fridge to kick on and off based on wort temperature, you will be able to keep the wort from getting to hot, but due to the fact that the fridge insulates so well (and with no instrument to heat), you will have a difficult time keeping the wort from getting too cold. It should be obvious. You want the wort at 65. Fermentation speeds up and the fridge kicks on. It is cooling the ambient air at a much faster rate than it is cooling the warm wort. Once the wort is reigned back in to 65, the fridge stops running, but it is still a huge insulated box full of ambient air that is well below 65. Where is the wort temp going to go at this point? It will drop like a brick (because there is no heater to keep it from dropping to "ambient", and by measuring the wort, you gave up your ability to control ambient). As I said, a regulated fridge/cold box is a good second option, but it is a distant second.

 

[jfowler1]

3) Only controlled heating of the air
This is far less common, but I have heard of brewers who live in a cold environment, and will build an insulated box with some type of heating element (like a heating pad or a light bulb). If the ambient temp falls, the heating element turns on. You have all the opposite problems of the controlled fridge. You will be okay at pitching, you will be okay as the wort ramps up to the desired temp (lets say 65) but then you have absolutely no way to pull in the reigns and the temp can easily swing higher than desired. Because you are using an insulated box (you have to for this method to be effective) there is not enough of a low end differential to regulate things. As I think about it, this method is actually closest to my "ideal scenario 1", but the wort has to have enough access to cool ambient air and have a powerful enough heating source to offset that cold air. And at the core of the problem, it is most likely that a brewer using this set up is still taking his measurements based on ambient, which as I've said many times, is always a poor measurement of wort temp. The best set up for this scenario would be a cold basement (55F) and a fermwrap, a johnson controller, and a thermowell. In this case, the basement is acting like a giant fridge, so in reality, you are getting the combination of a cool ambient temp and a controlled heated carboy. However, this is also geographically and seasonly dependent, and unlike my fridge set up, you can't ferment a true lager (but lagering would be another thread all together).

4) A semi-controlled environment that falls in the suggested temperature range for the yeast.
Finally, this is the scenario I have to imagine fits most brewers. This is that interior closet, the Alton Brown bath tub, the basement corner - basically anywhere a temperature is stable and reads 65 (keeping with my ale example). You are not doing anything wrong, but it is simply cutting the yeast loose to do what they want. Temps will climb at the peak of fermentation, and they will fall at the end. This is like entry level CJOHB fermentation control. Personally, I think you would be much better off in this case going a small step further and fermenting in an ice bath, or with one of the draped wet t-shirt methods, because the increase of temps too high is a bigger problem than keeping temps too low. Yeast are not happy cold, but they will still work. They will work slow, but clean.

 

[jfowler1]

So as you can see, there is a clear difference between controlling the wort temperature and controlling the ambient temperature, but you really need to control both to control fermentation.

As I mentioned, most people are happy picking up the ability to control one factor, but at that point you are so close to being able to control both, why not just do it? I think my explination is pretty solid, and the benefits/disadvantages of the 4 methods I laid out are pretty tough to argue against. I have seen first hand how precise control improves your ability to consistantly ferment beer - if I didn't have such experiences, I would not be taking the time to explain its merits. You don't need a set up like mine to make hit a perfect fermentation, but it certainly doesn't hurt. I am sure BOS beers have been fermented in a closet, but sometimes, even a blind squirrel finds a nut.

Does the whole thread make sense now?

Joe

 

[Catt22]

Does the whole thread make sense now?

No, and don't take it personally, but I disagree with just about everything you've listed. I can see you are certain of your conclusions and your methods are working for you, so it's all good. I am just not convinced that having a heating unit competing with the cooling unit is the best way to go. It would make more sense to me if you used a two stage controller with a dead band and had it set up to either heat or cool the chamber, but not both simultaneously.

 

[scruffymmh]

Point well taken, but my major limitation is that i have two, single stage controllers. Also, using the beer temp to regulate your cooling and heat sources risks over-running beyond some desired temp range. Example: fridge freezes other items therein b/c the cooling effects of the fridge tuning on take a significant amount of time to affect your wort temp (where temp probe is positioned).

 

[Catt22]

Also, using the beer temp to regulate your cooling and heat sources risks over-running beyond some desired temp range. Example: fridge freezes other items therein b/c the cooling effects of the fridge tuning on take a significant amount of time to affect your wort temp (where temp probe is positioned).

I do agree that having a probe in the keg or fermenter is not the way to go. I've been testing this for the past week or so. Right now I have a one gallon jug in the freezer. The Johnson A419 probe is in a thermowell in the jug. I have a wireless digital min/max thermometer in the jug of water as well. The temperature of the water in the jug swings 3.4 degrees from minimum to maximum with the differential set to 1*F. With the probe in the air I can hold the temps to about a one degree swing. ie +/-1 degree from the setpoint using a 4 degree differential. When cooling (or heating) a fermenter, so long as the wort is sufficiently cooled prior to pitching, I have no trouble keeping up with the heat generated by the yeast activity. I think that the fan continuously moving air over the fermenter helps tremendously with this. Without a min/max thermometer or some other way to track the temperature swings, it would be near impossible to know what's going on. Spot checking the thermometer or the controller reading now and then isn't good enough IMO.

 

[jfowler1]

Catt22,

What are your thoughts about this recent thread?

https://www.homebrewtalk.com/f163/temperature-control-fermentation-241790/

Isn't the problem the OP is having in that thread exactly the drawback I laid out when I discussed using a controller to keep the air at fermentation temps?
The freezer in this person's case is doing a good job of keeping temps from getting too high, but once the carboy is cooled, the temp drops too low due to the now "ultra cold" ambient temperature.

I agree that in a stable liquid (or maybe a small amount of liquid), the ambient temperature is probably good enough. Air temperature would be stable, liquid temperature would be stable, and given how well insulated a fridge/freezer is, there would be very little movement in temperatures that require turning things on and off. However, don't you think that a liquid with a more dynamic temperature point (like a fermenting wort) would create a lot more need for heat to fire, and/or a fridge/freezer to go into a chilling cycle? That 5G carboy is like a moving target, and I just do not see how a single instrument can be as effective. Other posts (like the one I liked above) prove the difficulty you would have.

So again, in a stable environment (like a keezer for example) I am sure that a single control of ambient will suffice, but for something as dynamic as 5G of fermenting wort that can easily jump to 10 degrees above ambient temperatures, I simply do not believe that a single control is adequate.

I got it!
I reread your post, and it suddenly became clear where we are missing one another. You ferment in a fridge, but you are not measuring wort temp, you are measuring the temperature via a thermowell in a one gallon jug (of water I assume). More so, you have your min/max thermometer in said "jug". In other words, you are monitoring the jug, not the beer. That falls right into my point that ambient temp does not equal wort temp. Essentially, you are putting your carboy in a stable interior closet, and putting a high/low thermometer in the closet. You see the ambient temps (in your case, a jug of water) are relatively stable in the closet (fridge) all day and all night, which is nice, but you are not fermenting a jug of water, you are fermenting 5 gallons of wort.

Your jug is kept nice and stable, but the carboy is free to raise as it wants as fermentation activity increases and generates its own heat. It is going through that heating process, and all the while, you are blind to it happening because you see the temps in the jug are perfectly fine. Just like that stick on carboy thermometer that reads 70F despite the max/min thermometer in the closet showing stable temps all day and night.

Simply put, you built the world's most precisely controlled closet.

Is that clearer?

Joe

EDIT - Now, if you tell me that during fermentation, you take the min/max thermometer from the jug of water and put it in your carboy and only see a one degree swing in the wort, then you are on to something. I simply do not think that is what you said you are doing (but I could be reading this wrong).

 

[Catt22]

My thoughts on that thread are that IMO he'd have better luck with the probe in the air and not in the liquid.

Yes, the current test is with a one gallon jug of water. Obviously, the jug has less thermal mass than a 5 gallon keg or carboy, so it will fluctuate more than the larger volume. That's a no-brainer.

Next test will be with a fermenting batch of beer. The min/max thermometer will be in the beer and the probe will be mounted in the air stream of the fan with the fan running continuously. I have to wait for the next batch to give this a try. I don't think I will have any trouble keeping the fermenter within a degree or two of the target. I've done this test before, but with the thermometer (not the controller probe) attached to the outside of the fermenter. I had no trouble holding the desired temp, but I did have to adjust the set point (adjusted up) as the ferment finished out. I'll post back when I have the results in a week or so. I will probably do a third test as well with the controller probe in the fermenter along with the min/max thermometer.

Where are your test results? So far, all I've seen is a bunch of speculation with an occasional grab sample here and there. Not really very scientific and very prone to preconceived outcomes IMO.

 

[jfowler1]

I look forward to hearing your results using the min/max thermometer in fermenting wort while regulating the fridge temp based on a probe in a jug of water.

If your experiences are anything like mine, you may change your opinions. If not, you can change mine.

I do not really know what you want in terms of "test results". You are not satisfied to see a picture of a carboy set to 62F (with a 1 degree differential reading 61F while not even firing a heater) with a probe in a thermowell in the middle of the wort?

As the thread progressed, I checked the ambient temp of the fridge with a kitchen probe thermometer and got a reading of 48F.

So in review, these are facts - the ambient in the fridge is 48, the probe in the wort is reading 61F, and the desired temperature max is 62F. If the wort cools to 60, the heater will fire, it will raise to 62, and turn back off. That is not a cycle you can sit and watch (unless you really have some time to kill).

What more of a "test" could you possibly want? I am showing you a system in practice while fermentation is taking place, not some "theory".

Aren't pics still on page 2?

Joe

 

[Catt22]

I look forward to hearing your results using the min/max thermometer in fermenting wort while regulating the fridge temp based on a probe in a jug of water.

That's not the plan. The controller probe will be in the air stream of the continuously running fan. The min/max thermometer will be inside the fermenter.

If your experiences are anything like mine, you may change your opinions. If not, you can change mine.

I'm open to changing my opinion on this, but I would have to see some very convincing evidence before I did and I haven't seen any yet.

I do not really know what you want in terms of "test results". You are not satisfied to see a picture of a carboy set to 62F (with a 1 degree differential reading 61F while not even firing a heater) with a probe in a thermowell in the middle of the wort?

Right, the picture alone doesn't do it for me. I would want to see the min/max points for a 24 hour period plus some detail on the fridge unit size, contents etc.

As the thread progressed, I checked the ambient temp of the fridge with a kitchen probe thermometer and got a reading of 48F.

Good for you! Did the ambient temp change any when you opened the door? It always does on mine when I do that.

So in review, these are facts - the ambient in the fridge is 48, the probe in the wort is reading 61F, and the desired temperature max is 62F. If the wort cools to 60, the heater will fire, it will raise to 62, and turn back off. That is not a cycle you can sit and watch (unless you really have some time to kill).

I suspect that the wort will continue to cool below 60 before the heater can warm it back up and the same will happen when as it passes 62. I'm pretty sure it will coast somewhat higher. This is where the min/max thermometer can help. Without some way of logging the minumum and maximum temperatures, you don't really know what the swing is. But, not to worry, you can always fall back on speculation.


What more of a "test" could you possibly want? I am showing you a system in practice while fermentation is taking place, not some "theory".

Aren't pics still on page 2?

Sorry, the pics don't do it for me.

Joe

...

 

[jfowler1]

Okay, we can do things that way if it makes it easier. This will be my last try.

I look forward to hearing your results using the min/max thermometer in fermenting wort while regulating the fridge temp based on a probe in a jug of water.

That's not the plan. The controller probe will be in the air stream of the continuously running fan. The min/max thermometer will be inside the fermenter.

OK, so to make sure we are clear. The min/max thermometer will be in the fermenter (that is word for word, so I am pretty confident) and will show you your min/max swings. That sounds like a great idea. The controller probe will be in the "air stream" of the fan. So making sure I understand, you will set your controller for say, 65, put the probe in the "airstream" of the fan. Right? And your assumption is that the temperature of the fermenting wort will be the exact same temperature the probe is reading in the "airstream". Please confirm that I am correct there.

If your experiences are anything like mine, you may change your opinions. If not, you can change mine.

I'm open to changing my opinion on this, but I would have to see some very convincing evidence before I did and I haven't seen any yet.

OK

I do not really know what you want in terms of "test results". You are not satisfied to see a picture of a carboy set to 62F (with a 1 degree differential reading 61F while not even firing a heater) with a probe in a thermowell in the middle of the wort?

Right, the picture alone doesn't do it for me. I would want to see the min/max points for a 24 hour period plus some detail on the fridge unit size, contents etc.

Well, I think we may just have a disagreement/misunderstanding - whatever you want to call it - about how a temp controller in the wort is working. You see, its job is regulating a min/max. I have it set for 62, because with this yeast, I never want it to go above 62. 62 is the max. That's it. It is very simple. The second the probe reads 62, the heater turns off. There is no carry over, it never hits 63. So now the heater is temporarily off. As the temp slowly drops, the probe (which for the sake of repeated clarity is reading wort temp, not "airstream" temp) will wait until it registers 60F. The second it is at 60 F, it starts to heat. It never drops below 60F. In all honesty, it is at 61F 95% of the time. Don't worry about a 24 hour period - I can guarantee this process for a 4 week period. Unless I tell it to, the temp will always be between 60F and 62F, with the majority of the time at 61F. That is how these units work in a two stage system. It is their job.

As the thread progressed, I checked the ambient temp of the fridge with a kitchen probe thermometer and got a reading of 48F.

Good for you! Did the ambient temp change any when you opened the door? It always does on mine when I do that.

Ambient temp does change when you open the door. I put the kitchen probe in the fridge, closed the door, came back an hour later, and it read 48F. I went into the garage the next morning, looked again, and the fridge is still 48F. Why? Because there are very little swings in ambient air (which is the same reason your little jug had such little differential during your tests). Give me a little more credit than to just stick a probe in and call it a day.

So in review, these are facts - the ambient in the fridge is 48, the probe in the wort is reading 61F, and the desired temperature max is 62F. If the wort cools to 60, the heater will fire, it will raise to 62, and turn back off. That is not a cycle you can sit and watch (unless you really have some time to kill).

I suspect that the wort will continue to cool below 60 before the heater can warm it back up and the same will happen when as it passes 62. I'm pretty sure it will coast somewhat higher. This is where the min/max thermometer can help. Without some way of logging the minumum and maximum temperatures, you don't really know what the swing is. But, not to worry, you can always fall back on speculation.

I agree, I would love to have a min/max thermometer just for the sake of a second instrument to prove myself, but maybe you just have to trust a years worth of experience with this equipment and take it at face value that the min/max of the wort I am measuring is what the thermometer in the wort is designed to regulate. There is some carryover, which is why you have a 1 degree differential. To say there is no carry over would mean the wort is at 61F 100% of the time - to say that would be lying. Again, I have been measuring fermentation temps of the wort this way for some time now. One of us is using actual experience, the other is falling back on speculation. You need to reevaluate a bit there.


What more of a "test" could you possibly want? I am showing you a system in practice while fermentation is taking place, not some "theory".

Aren't pics still on page 2?

Sorry, the pics don't do it for me.

Then clearly nothing will.

I have one simple question I would like you to answer. You put your carboy in the fridge and get it to pitching temp. You pitch, and set your probe, which is in the air stream, to cool to 65F (for sake of example). What is your wort temperature 24 hours later? You know the "air stream" temp, but what is your wort temp?

Please, enlighten me.

Joe

 

[Catt22]

Please, enlighten me.

Joe

Thanks, but no thanks. It has become obvious to me that the effort would be wasted.