Fermenting in a temp controlled freezer

[stuknkrvl]

Hey all,

I'm using a temp controlled freezer for the first time, and the fermentation seems different than what I've seen in the past using the old swamp cooler method.

I pitched on 8/31 with a liter sized starter. My experience has been that the fermentation pretty much finishes up and the krausen drops out somewhere around day four or five, but it's now day nine and there's still a pretty thick krausen at the top of my carboy and there's a lot of bubbling along the inside of the carboy (although very little action in the airlock).

Have you had similar experiences? Is it normal for the fermentation to take a little longer when the temperature is more tightly controlled?

I should probably check a gravity reading, but to quote some advice I got here once, I'm trying not to dick with it.

Thanks!

 

[TexasDroughtBrewery]

I think this would make since b/c the warmer you have the fermentation usually the faster it would go. So, if you went from like room temp inside of a dark closet to a colder more controlled temp then yeah..I can see how that might "slow" it down.

 

[Xlimey]

As I usually brew Double IPAs I rely on my air conditioner set to 75F to control its primary fermentation. Before reading this article I didn't know that Lagers require such low temps during fermentation. That said, is 75 too high for beer/ale primary fermentation? If so then I need to think about alternative chilling methods even though my beers seem to taste ok.

 

[Yeastieboy]

It totally depends on the temperature you're holding in that freezer and the yeast you're using. I tend to ferment at or slightly below the manufacturer's lowest "recommended" temperature which usually requires two weeks in the primary to dry up. And yes, the Krausen takes 7-10 days to recede vs. 4-6 when fermented at say, 65F.

 

[kh54s10]

What wort temperature were you able to maintain with the swamp cooler, How does this compare with the wort temperature you maintain with the fermentation chamber.

Are you using a different yeast?

If you are maintaining a colder wort temperature or using a different yeast your timetable of activity could easily be longer.

As I usually brew Double IPAs I rely on my air conditioner set to 75F to control its primary fermentation. Before reading this article I didn't know that Lagers require such low temps during fermentation. That said, is 75 too high for beer/ale primary fermentation? If so then I need to think about alternative chilling methods even though my beers seem to taste ok.

Fermentation is exothermic. Your 75 ambient temperature could easily allow your wort to get as high as 85 degrees.

Even at 75 degrees it is too warm. You will be getting some off flavors. How bad they are depends on how hot and how discriminating you are to the flavors of your beer.

Most ale yeasts do best in the mid sixties F.

 

[stuknkrvl]

This batch is with WLP004 Irish ale strain. I've used it a couple times before and it's always performed very well for me.

@kh54s10 - Previous to this batch, I've been limited to a plastic stick-on thermometer on the outside of my carboy. I worked really hard to maintain the temp at or around 66-68 F. I kept a fermentation temp log, checking it at least three times each day, adding and removing frozen water bottles as needed. The temp usually stabilized and didn't require any additional tweaking after about four days, right around the time the krausen dropped out. Needless to say, it wasn't exactly stable throughout the most active phase, but I like to think I kept it fairly well regulated. This batch is in the freezer with the dig temp controller set to 68 (White Labs website says this strain digs 66-68F), temp probe up against the outside of a glass carboy, insulated with a couple folded over paper towels, and secured with duct tape. I check it at least once a day (it's my first time using this set up, so I'm a little paranoid), and it seems to be holding very steady.

I'm maintaining a solid RDWHAHB attitude about it all, especially considering my standard MO is to let my beers go a solid two weeks before going in for a gravity check and/or bottling. I'm just curious if anyone else had experienced "delayed" fermentations after upgrading from a swamp cooler to a temp controlled ferm chamber.

 

[stuknkrvl]

This all makes me wonder - Should I be checking my gravity more often now? I mean, could it be that I just need to go ahead and cold crash it once it gets to the FG I want?

 

[Yeastieboy]

You must be keeping the wort a few degrees cooler in the freezer, simply resulting in a slower fermentation. You're on day 8. I agree with your standard M.O. of a solid two weeks primary. I do the same by default. Take a reading on the 14th. Assuming all went well on brew day, I'll bet you hit you're FG. Don't cold crash now unless you get the same gravity readings several days apart. If it's not where you want it, wait the two weeks.

Assuming you're not using a thermowell to get the probe into the wort, I personally would have started WLP004 at 60F, banking on the fact that the initial stages of primary fermentation will quickly take the wort itself to 64F(ish). If I had my probe in the wort, I'd set it at 64F. After 3-4 days I'd then raise the wort temp to 65/66F and maybe again to 67/68F for the last 2-3 days. But that's just me.

 

[stuknkrvl]

Yeah, I'm still figuring out the finer points of fermentation temps. I've seen a lot of people suggesting a stepped temperature profile, I'm just not sure my game is quite there yet.

I bought a stopper with an extra long thermowell that's supposedly designed specifically with the Johnson digital temp controller in mind. The probe fits in the thermowell like a boss, but the damn stopper is too small for my carboy - a fun fact I discovered after I had pitched the yeast! Poor planning on my part, obviously, but I'm sure my LHBS holds the cure for my ills.

 

[Xlimey]

What wort temperature were you able to maintain with the swamp cooler, How does this compare with the wort temperature you maintain with the fermentation chamber.

Are you using a different yeast?

If you are maintaining a colder wort temperature or using a different yeast your timetable of activity could easily be longer.



Fermentation is exothermic. Your 75 ambient temperature could easily allow your wort to get as high as 85 degrees.

Even at 75 degrees it is too warm. You will be getting some off flavors. How bad they are depends on how hot and how discriminating you are to the flavors of your beer.

Most ale yeasts do best in the mid sixties F.

If I take the extra step of fermenting in an electronically controlled mini fridge set at say 65F, does that mean that it is also best to leave it in there until such time that it is ready to be kegged? Then the next question would be whether ales sitting in a sealed Corny Keg at 75F would deteriorate over time?

 

[Yeastieboy]

Yeah, I'm still figuring out the finer points of fermentation temps. I've seen a lot of people suggesting a stepped temperature profile, I'm just not sure my game is quite there yet.

I bought a stopper with an extra long thermowell that's supposedly designed specifically with the Johnson digital temp controller in mind. The probe fits in the thermowell like a boss, but the damn stopper is too small for my carboy - a fun fact I discovered after I had pitched the yeast! Poor planning on my part, obviously, but I'm sure my LHBS holds the cure for my ills.

Once you have a stopper that fits, that's going to be your ideal setup. Then you can really dial in the wort temp directly.

Stepping the temp isn't necessary, especially if you are using a thermowell to get a more accurate temp reading. I still suggest starting at or slightly below the yeast manufacturer's lowest recommended temp and letting it ride for two weeks. That's typically going to get you the "cleanest" beer IMO.

 

[stuknkrvl]

@Yeastieboy - So with this brew, for example, set the temp to, say, 64 F and just let it do it's thing at that temp for the entire two weeks? Would you ever want to ramp up the temp a couple degrees?

 

[Yeastieboy]

@Yeastieboy - So with this brew, for example, set the temp to, say, 64 F and just let it do it's thing at that temp for the entire two weeks? Would you ever want to ramp up the temp a couple degrees?

Yeah, like I said a few posts back; If I had my probe in the wort, I'd set it at 64F. After 3-4 days I'd then raise the wort temp to 65/66F and maybe again to 67/68F for the last 2-3 days. But that's just me. Leaving it at 64F, for example, the entire time should be perfectly fine. I sometime ramp simply because it's my understanding that diacetyl is formed in the first few days if temps are to high. Therefore, I start lower and inch it up a bit later to help keep the yeast working and finish the beer.

 

[stuknkrvl]

Thanks for the tips! I'm brewing a pumpkin ale pretty quick. Using Wyeast 1450 Deny's Favorite 50 for that one. I'll try stepping the temps on it and see how it turns out. I'll keep you posted.

 

[kh54s10]

If I take the extra step of fermenting in an electronically controlled mini fridge set at say 65F, does that mean that it is also best to leave it in there until such time that it is ready to be kegged? Then the next question would be whether ales sitting in a sealed Corny Keg at 75F would deteriorate over time?

I have usually just kept the same temperature. But, my last one seems stalled at 1.030 so I took it out of the chamber. Often the suggestion is to keep the cool temperature until fermentation slows then ramp it up to 68-70 degrees.

Ales will deteriorate over time. Slower at lower temperatures and how quickly or how bad it gets depends on the recipe. I have made a couple of big beers that took a year to come into it's own and another year to 3 years before they noticeably declined. On the other hand an IPA will start losing it's punch within weeks of being packaged.

 

[stuknkrvl]

Day 12. Krausen still thick as all get out, still some slow trickling bubbles on the inside of the carboy, no action in the air lock that I noticed.

I haven't pulled a sample for a gravity reading as of yet (patiently waiting my full two weeks), but I'm starting to get worried that maybe my fermentation is stuck?

I don't know.

Thoughts?

 

[Yeastieboy]

Pull a gravity sample!

 

[stuknkrvl]

Pull a gravity sample!

I know... I know...

I'll pull one early on the morning of the 14th and see where it stands.

Assuming it's stalled - can I ramp up the temp to get the yeast kicking again?

Assuming it's completed - just cold crash it and carry on?

 

[Yeastieboy]

If it's ready, it's ready. Otherwise, the first step I would take is increasing the temp a few degrees and gently swirling (not splashing) to agitate yeast into suspension. If the gravity doesn't come down at all after 48 more hours and it's way above what's correct for your brew, you'd need to repitch some fresh yeast and hope there's enough available oxygen to allow a complete fermentation.

Available oxygen in wort was an ongoing issue for me until I started aerating with pure O2.

 

[stuknkrvl]

If it's ready, it's ready. Otherwise, the first step I would take is increasing the temp a few degrees and gently swirling (not splashing) to agitate yeast into suspension. If the gravity doesn't come down at all after 48 more hours and it's way above what's correct for your brew, you'd need to repitch some fresh yeast and hope there's enough available oxygen to allow a complete fermentation.

Available oxygen in wort was an ongoing issue for me until I started aerating with pure O2.

I aerate all my brews with O2. I hit this one for about a minute.

I'll check it in a couple days, see where things are.

 

[Northbank]

There are billions of yeast in there ... adding a few more won't change much if its the same strain. I used a chest freezer for mine as well, the last beer took a full two weeks before the Krausen subsided and it still left substantial yeast rafts. Just let it ride ... taking the gravity won't change anything, any O2 you put in almost two weeks ago is long gone.

 

[Yeastieboy]

Taking a gravity reading will tell him if he needs to let it ride or not. The initial questions were why is it taking longer than previous batches and is it finished...

 

[stuknkrvl]

Update -

OG on this batch was 1.070. Pulled a sample this morning, I'm at 1.019. Brewer's Friend says that clocks me in at 6.69%.

I'll take it!

Gonna rack this and let it sit with a couple vanilla beans for about a week before I bottle it up.

Thanks again for all the advice!

 

[Yeastieboy]

Tragedy narrowly averted! Cheers!

 

[whoaru99]

Update -

OG on this batch was 1.070. Pulled a sample this morning, I'm at 1.019. Brewer's Friend says that clocks me in at 6.69%.

I'll take it!

Gonna rack this and let it sit with a couple vanilla beans for about a week before I bottle it up.

Thanks again for all the advice!

1.019 might be right or it might not be. It's less a matter as to "I'll take it!", as it is to bottling, if not finished, the risk of bottle bombs.

 

[helibrewer]

Update -

OG on this batch was 1.070. Pulled a sample this morning, I'm at 1.019. Brewer's Friend says that clocks me in at 6.69%.

I'll take it!

Gonna rack this and let it sit with a couple vanilla beans for about a week before I bottle it up.

Thanks again for all the advice!

Probably done, your apparent attenuation is 73%, WLP004 is advertised at 69-74%

 

[stuknkrvl]

@whoaru99 - Planning to rack this one over to secondary with a couple vanilla beans. If it's still working a little, it'll have plenty of time.

 

[Yeastieboy]

Betchya it drops a few more points after sitting on the beans for a week or two. Good luck!

 

[Yeastieboy]

How's the beer coming along?

 

[stuknkrvl]

Very well!

View attachment 1474932765376.jpg

 

[stuknkrvl]

@Yeastieboy - Bottled up 17 bombers, nine 12 oz bottles, and one short pour, so just short of four gallons. The chocolate shines and the vanilla is subtle but obviously present. My only negative mark is that the smoked malt is too prominent. Next time I brew this I'll back down the smoked malt and just add in a couple extra ounces of base malt to make up the difference. All in all, very pleased with the way this came out. I racked it over to another carboy and tossed in the vanilla ten days ago, cold crashed it down to 35F for a day and a half before bottling. I'll check back in next week once these have had time to carb up and I've sampled the final product.

Cheers!