What does "Fermentation Temperature Control" mean? To you?

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cscade

cscade

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This is a deviousy simple question, but I think more than a few of you will kneejerk and go well, duh, it means this, only to second-guess yourselves.

When home brewers talk about fermentation temp control, what I hear them saying is environmental control. Keep the space your fermenter is in as constant a temperature as possible. Not the liquid inside the fermenter. This isn't hard.

However, as we are all aware, yeast produce heat energy as a side effect of doing their work. When a fermentation vessel is kept in a constant-temperature area (and I do mean perfectly constant) the temperature inside the fermentation vessel will still rise and fall in a curve from start of fermentation to completion. I've seen as much as 11f rise just from yeast activity in a fermenter kept in a dead-stable environment, depending on strain.

This is because air is a very poor conductor of heat. Regardless of how large the constant-temperature space is, as long as it is filled with air it will not dissipate (or normalize) the heat generated by the fermentation process.

Therefore, the only way to control the temperature of the fermenting wort itself is to actively dissipate, or apply, heat via some sort of metered mechanism.

Is this what we want? Will the yeast produce optimum results in a vessel that is allowed to change temperature, but only from, and relative to the heat the yeast themselves produce? Or, will they produce optimum results if their liquid environment is regulated to a constant temperature?

I ask this question only because until relatively recently on a historical scale, it would not have been possible for brewers to even cause the latter. Therefore, either we are now able to brew better beer than ever before by forcing the yeast to work in an artificial environment, or we are applying too much technology to what is really a simple problem.

When I hear the home brewing experts (John Palmer et all) talk about fermentation temp control, it is treated as the holy grail of good results. The most important element short of sanitation. How do we best apply it?
 
It is a simple matter of measuring the temperature of the beer, not the air.

Use one of these:

Straight-Wall Stainless Steel Thermowell for Carboy or Fermenter
TWell16.jpg


and a carboy hood, along with a temperature controller to maintain exact fermentation conditions.

Yes, it does make a huge difference.
 
I go by air temp. You have some excellent points though. Still im not going to go any more crazy on my set up then what i already have:)
 
Boerderij_Kabouter said:
It is a simple matter of measuring the temperature of the beer, not the air...
Click to expand...

So, then you're saying that we have only recently on a historical scale become able to brew truly good beer?

---

As an aside to everyone, I'm well aware of the equipment and options available, and I'm fully capable of designing and building my own fully automated digital control system if I decide to.

This is really meant to be a theory discussion to see if we've gone too far in one direction just because we can.

I concede that it's certainly possible that yeast will perform best under artificial conditions. I just want to dig into this and see if there's any possibility for misconception here.
 
ahhhh.... now I get what you are saying.

I think that beer has made huge leaps forward in the last century. The discovery and invention for thermometers and how to control temperature have drastically improved more than just beer.

I believe Spaten Brewery was the first to realize the overwhelming importance of temperature and began controlling there ferment temps with ice houses to attempt a more controlled environment and fermentation temperature schedule.

The advanced temperature schedules used by many professional breweries do account for the different phases of yeast growth and metabolism, changing the temperature according to ideals. Many homebrewers do this to some extent (D-rest, raise temp toward end to manipulate the attenuation limits of a yeast, etc.) but in general we are not as advanced as the pros.

In general, temp control is proven (at least IMO) to produce better beer, more consistently. You can easily produce good beer just keeping the ferm temps in range, but my consistency and overall product quality improved greatly when I when to a completely controlled system.
 
cscade said:
So, then you're saying that we have only recently on a historical scale become able to brew truly good beer?
Click to expand...

Keep in mind that on a historical scale, only recently have breweries been able to brew year-round, thanks to proper temperature control. Before temperature control, breweries would either stop brewing for the summer or only brew styles amenable to higher fermentation temps (Belgian Saisons or Hefeweizens for example). Octoberfest beers where typically brewed as the last beer in the spring before the weather got too warm and then lagered them all summer in the cooler cellars before being tapped in the fall.

Even back then, brewers knew that proper temperature control was essential to making good beer to style, but were limited on ways to control control it. Not so anymore.
---
cscade said:
As an aside to everyone, I'm well aware of the equipment and options available, and I'm fully capable of designing and building my own fully automated digital control system if I decide to.

This is really meant to be a theory discussion to see if we've gone too far in one direction just because we can.
Click to expand...

In my experience, my beer have benefitted greatly from temperature control. Frankly, I'm making beer that is as good and ass fresh as the craft beer I can buy for $10/6 pack. I don't know if its going too far. I'd probably not be too excited about brewing if I was drinking a bubblegum amber that fermented at 85F.

I think one of the main reason why many new homebrewers aren't happy with the beer they are making (and ultimately drop the hobby) is because they lack the understanding and/or equipment for better fermentation temperature control. Now more than ever we have available to us the best ingredients and information out there to make good beer. Combine that with proper temp. control and you really can make quality beer.

cscade said:
I concede that it's certainly possible that yeast will perform best under artificial conditions. I just want to dig into this and see if there's any possibility for misconception here.
Click to expand...

Its really not about making yeast perform their best, its about making the yeast perform consistently and to produce a quality product. I'm all for using technology to accomplish this. I'm not sure what you mean by a "misconception" here....:confused:
 
Boerderij_Kabouter said:
The advanced temperature schedules used by many professional breweries do account for the different phases of yeast growth and metabolism, changing the temperature according to ideals. Many homebrewers do this to some extent (D-rest, raise temp toward end to manipulate the attenuation limits of a yeast, etc.) but in general we are not as advanced as the pros.
Click to expand...

I agree that the pros have way more advanced equipment than us homebrewers do. However, it is amazing how well us homebrewers can do, with some relatively simple equipment at our disposal!

Back to the OP, I guess I'm missing the point as I don't view fermentation control as a particularly invasive thing for the yeast, nor do I agree that we are necessarily imposing artificial conditions on them.
 
I think air movement is an important facet of temp control in the vessel. I keep a fan in my fermentation chamber to move the air, and the plastic thermothingy on the bucket generally agrees with the air temp from the Ranco thermosensor.

In the lab, I use both air temp monitoring and direct monitoring for bacterial growth. When I have a bunch of small scale growths to do, I put them in flasks and put the flasks in a shaker and just monitor the air temp. This works well, as there is plenty of air movement. I can shift from 37C to 42C or 16C with ease. When I grow my bacteria in a fermentor (10 L or 120 L), I have a thermosensor in the liquid. Temp is controlled by the computer passing water through a jacket that surrounds the vessel.

I generally consider the water-jacket-with-direct-monitoring more accurate (and would love a jacketed vessel for home use!), but air temp monitoring works just fine in 99% of situations..
 
cscade said:
Therefore, either we are now able to brew better beer than ever before by forcing the yeast to work in an artificial environment, or we are applying too much technology to what is really a simple problem.
Click to expand...
I don't consider a temp controlled environment "artificial", since we are basically just simulating the temperatures that are ideal year round instead of being limited to only brewing during winter months. That is like saying since bacteria want to make a home in your wort, sanitation is making "artificial" beer.

In addition I would say that by today's standards, beer has only been great in the more recent years. I have no way to prove this but all historical texts I have read suggest that beer did not last very long due to high level of contaminates and was also smokey due to wood fired kilning. Malts were also kilned very dark in comparison to today's malts, making beers less consistent and basically cutting off all pale styles we now know of. If I had to guess I would say the beer we drink now is exponentially better than the beer people were drinking more than 100 years ago.

As for how I measure temp I put the temp probe up against the carboy and then tape a piece of foam over it. Every time I have measured the actual beer inside it was within 1 degree of what the temp controller said.
 
cscade said:
So, then you're saying that we have only recently on a historical scale become able to brew truly good beer?

---

As an aside to everyone, I'm well aware of the equipment and options available, and I'm fully capable of designing and building my own fully automated digital control system if I decide to.

This is really meant to be a theory discussion to see if we've gone too far in one direction just because we can.

I concede that it's certainly possible that yeast will perform best under artificial conditions. I just want to dig into this and see if there's any possibility for misconception here.
Click to expand...



Your use of the term "artificial" doesn't make sense to me in this context.

It's kind of like saying that any time you heat something up to cook it, it's artificially made because you controlled the temperature of the food.

I see your overarching point about technology, but I think aiming it at temp control is way off the mark.
 
maybe a little off topic but this is why I prefer to use a swamp cooler I can easily maintain 64° temps of the water and my digital thermometer in the wort says its 2°-3° higher during fermentation. Water will wick away heat faster than air whether the air is moving or not .I have a small fridge that I used to use to ferment all my beers in now its used to lager only.

I can sit outside all day in shorts all day long at 70° try being in a pool at the same temp for a while.And I put out more heat than yeast do per minute.
 
cscade said:
When home brewers talk about fermentation temp control, what I hear them saying is environmental control. Keep the space your fermenter is in as constant a temperature as possible. Not the liquid inside the fermenter. This isn't hard.
Click to expand...

I control ambient temps and don't worry about it too much. The jump from no temp control to ambient control was huge. I suspect ambient to internal (given additional sanitation exposure and expense) is diminishing returns for me.
 
I also control temps by taping the probe to the side of the glass fermenter. I cover it with bubble wrap to insulate it from the air. This way the freezer will drop to whatever temp it needs to keep the wort where I want it. I see this as giving them the optimal conditions to make good beer, just as if I had a cave to put them in at the very start of fermentation and moved them to warmer spaces as fermentation dropped off.
 
cscade said:
So, then you're saying that we have only recently on a historical scale become able to brew truly good beer?
Click to expand...

A lot of the European breweries (especially the ones making lagers) did their fermentation in caves that were cool year round. I went to the Pilsner Urquell brewery a few summers ago and their brew caves were close to freezing even though it was 90 out. In an unrelated note, they had a version of their beer that was pretty fresh and unfiltered and it actually was unskunked and had great flavor.
 
Great discussion everyone!

Looks like my references to "misconceptions" and "artificial" were curve balls. Here's a little background on my thought process;

I got started on this question because I'm a home brewer by night, and a historic structure restoration professional by day. Working with buildings and materials that exceed the 100 year mark on a daily basis, I am exposed to materials and techniques long since forgotten in modern times. Often, the materials we use today in identical situations, are inferior to what was used 100 years ago. Even though the modern materials are now the de-facto standard, their rise to the top was not driven by their quality or durability, but rather by their ease of manufacture and installation.

Take for instance plywood sheeting. Plywood sheeting became popular because it could be manufactured in consistent sizes, shipped easily, and installed by just about anyone quickly over large areas. Often, you don't even have to cut it to size. Just nail it down. Prior to plywood, solid wood boards were used as sheeting. They were harder to ship and handle, more likely to distort or twist before installation, had to be individually cut to length when installed, and required more thought and planning to develop a good inventory for construction.

It's easy to see why plywood became popular. In pretty much every way, it was easier. I can rattle off any number of materials which were replaced for exactly the same reason.

Now, you walk up to a modern construction worker and you ask him to use solid wood sheeting instead of plywood, an he looks at you like you're crazy. "Why would I want to use boards? That would be much harder." he's likely to say. He's never done anything else. He knows how to nail down plywood sheeting. And, when it's time for him to teach his son how to be a construction worker, he will teach his son how to use plywood sheeting, without ever giving it a second thought. After all, to him, it's just what you do.

What he doesn't know, is despite it's relative difficulty when you're installing it, solid wood sheeting is better over the life of the building in pretty much every way. It is much less likely to rot. It can breathe. It is stronger. It won't fall apart when the glue in it fails (there's no glue to fail). On and on.

But all of this information is lost because what is taught is what is easy.

Whew. What a rant.

So, back on topic, the brewers who socked their beer away in caves knew they were making better beer than the brewers who didn't. They learned that temperature control was important, and how to make it happen with the options they had available to them. In those circumstances though, they were controlling the environment of the fermenter, not the contents of the fermenter.

When it became easy to use technology to control the fermenter itself, without needing to control the ambient temperature, of course it made good sense for commercial breweries to do exactly that. It allowed them to brew multiple recipes simultaneously while keeping the room a comfortable temperature for their workers. It also allows them to punch up 65f on a control panel and totally forget about it. Now that is easy.

Now we, as home brewers, want to be like the big guys. I get that.

I just want to step outside of the obvious and ask: "Does controlling the liquid temperature instead of the environmental temperature actually make better beer, or is it just easier?"
 
I go by air temperature on the side of my Sanke fermenter inside a chest freezer. I am thinking of filling my freezer with glycol or something and having a stirrer added to agitate the fluid around my keg. Due to the way I ferment I can't get a probe inside the keg to measure that temperature, but I feel with enough brews under your belt the process can be streamlined to know what you are at inside. Not to mention, with an inside temperature probe the outside walls would always be cooler anyway. So I feel safe measuring from the outer wall of a stainless vessel.
 
cscade said:
I just want to step outside of the obvious and ask: "Does controlling the liquid temperature instead of the environmental temperature actually make better beer, or is it just easier?"
Click to expand...
It makes better beer, but the question of ease is negligible since the only extra effort required is taping a piece of foam over your temp probe.

Example: Last winter I brewed a Belgian Barleywine with an OG of 1.134. My garage was in the mid 50s, so I put the beer out there since I knew it would get warm once active and I had a lager going in my temp controlled fermentation chamber. By the time it was at peak krausen the beer inside the fermenter was at 74F, a difference of approximately 20 degrees between ambient and liquid temps. Now I know most beers don't generate that much heat, but it shows that ambient and actual liquid is no small difference.
 
cscade said:
Great discussion everyone!

Looks like my references to "misconceptions" and "artificial" were curve balls. Here's a little background on my thought process;

I got started on this question because I'm a home brewer by night, and a historic structure restoration professional by day. Working with buildings and materials that exceed the 100 year mark on a daily basis, I am exposed to materials and techniques long since forgotten in modern times. Often, the materials we use today in identical situations, are inferior to what was used 100 years ago. Even though the modern materials are now the de-facto standard, their rise to the top was not driven by their quality or durability, but rather by their ease of manufacture and installation.

Take for instance plywood sheeting. Plywood sheeting became popular because it could be manufactured in consistent sizes, shipped easily, and installed by just about anyone quickly over large areas. Often, you don't even have to cut it to size. Just nail it down. Prior to plywood, solid wood boards were used as sheeting. They were harder to ship and handle, more likely to distort or twist before installation, had to be individually cut to length when installed, and required more thought and planning to develop a good inventory for construction.

It's easy to see why plywood became popular. In pretty much every way, it was easier. I can rattle off any number of materials which were replaced for exactly the same reason.

Now, you walk up to a modern construction worker and you ask him to use solid wood sheeting instead of plywood, an he looks at you like you're crazy. "Why would I want to use boards? That would be much harder." he's likely to say. He's never done anything else. He knows how to nail down plywood sheeting. And, when it's time for him to teach his son how to be a construction worker, he will teach his son how to use plywood sheeting, without ever giving it a second thought. After all, to him, it's just what you do.

What he doesn't know, is despite it's relative difficulty when you're installing it, solid wood sheeting is better over the life of the building in pretty much every way. It is much less likely to rot. It can breathe. It is stronger. It won't fall apart when the glue in it fails (there's no glue to fail). On and on.

But all of this information is lost because what is taught is what is easy.

Whew. What a rant.

So, back on topic, the brewers who socked their beer away in caves knew they were making better beer than the brewers who didn't. They learned that temperature control was important, and how to make it happen with the options they had available to them. In those circumstances though, they were controlling the environment of the fermenter, not the contents of the fermenter.

When it became easy to use technology to control the fermenter itself, without needing to control the ambient temperature, of course it made good sense for commercial breweries to do exactly that. It allowed them to brew multiple recipes simultaneously while keeping the room a comfortable temperature for their workers. It also allows them to punch up 65f on a control panel and totally forget about it. Now that is easy.

Now we, as home brewers, want to be like the big guys. I get that.

I just want to step outside of the obvious and ask: "Does controlling the liquid temperature instead of the environmental temperature actually make better beer, or is it just easier?"
Click to expand...

My thoughts:

In regards to your "rant", I see you points about boards being better than plywood. The question I feel that you missed was: How MUCH better are boards than plywood? In my experience (which admittedly is substantially less than yours), my answer would be "not much". Every drawback of plywood you mentioned, while it is a recognized drawback, isn't MUCH of a drawback, assuming that you take care of the plywood (protect if from moisture being the biggie). Combine that with easy of installation, price, and it being much more eco-friendly then I can understand why its a standard material in today's buildings.

OK-so back to beer. Lets assume that controlling ambient temperature is better than controlling the temperature of the fermenting beer (although you never presented an argument why we should conclude this in the first place, your OP simply stated that this was true). As with your board vs. plywood example, you next have to ask: How MUCH better is controlling ambient temp vs. the temp of the beer itself? Again, I can't see much difference between the two and would answer "not much". So we are left with whatever method is most consistent, most cost-friendly, and easiest. It turns out that for both commercial breweries and the home brewer, its controlling the fermentation temp of the beer itself.

Sure, I could dig a cave in my backyard to ferment my beers because that is how my ancestors made beer, but why should I when I can use a $50 Ranco and a chest freezer to do the same thing with more consistency and less effort? I have a appreciation how they brewed beer back in the day, but that doesn't mean that is how I have to do things necessarily.

Maybe you could back up and tell us why exactly you feel that controlling ambient temps is the preferred way to control fermentation temps? Also, maybe you could tell us why you think the two methods are really all that different?
 
But now you have to define "better".

I'd say that modern technology allows for consistency. Same temp = same flavor profile from the yeast; whether it is better or not is up to the individual. ;)
 
I put my glass carboys in a water bath that I cool with ice and ice packs. When the krausen starts to fall I stop adding ice and let it naturally warm up to room temp. It's way easier and way more flexible for me to control the fermentation temp using a water bath than to try to control the room/ambient temp with 'swamp' methods (I live in uber-humid Florida). But I admittedly don't know the actual temp of the beer...but since the carboy is in a water bath I'm pretty sure the fermenting beer is fairly close to the water bath temp. In either case, I'd be tweeking the fermentation/ambient temp until the beer tasted better so it's not that big of a deal either way imo. 'Not cool enough' is still 'not cool enough' either way...tweek it down...rinse and repeat until the beer tastes better.

Seems to me that either way, when done right, could be great and either way, when done wrong, could suck. And both ways could achieve the exact same temp profile throughout a fermentation.
 
so........
I'm seeing a fermentation chamber with several conduits running within the vessel (for larger contact surface area) that open to the water/glycol bath, pumped to recirculate, with possibly a secondary heat exchanger (coil) for temperature adjustment (ice bath or small refridge). All PID controlled via probe submerged within the vessel. Hmmmm

That sure beats my T-shirt over the carboy in the water bath with the thumb controlled fan I have been using.
jason
 
If you tape the probe from your controller to the side of the fermenter in a fridge or freezer, the internal temp of the beer will be within one half a degree of the external temp of the fermenter during fermentation. This is according to some dude's test that Jamil talked about on one of the BN shows. This is one of the reasons I don't use a thermowell. The other reason is blow off from big starters, lots of O2 and 6.25 gallons in a 6.5 gallon carboy:)
 

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