More exBEERiments regarding temp control?

[Peruvian802]

I've read the brulosopher's 3 exBEERiments regarding fermentation temp control and generally it suggests that (in his experience) there is little ability for beer drinkers to pick out the one that was fermented at a different temp.

This obviously flies in the face of most homebrewers that decry that the single most important upgrade/investment/effort is temperature control.

Can anyone point me to more 'scientific' efforts to verify that temp control is so critical? I'm not talking about trying to lager at 85f or ferment a saison at 50f. I mean if my temp is within a 5 degree range for most beers, am I or anyone else going to notice it?

Thanks.

 

[Jakor]

I think some people would be surprised to see how far off their calibrations are for their temperature probes. Even if you are calibrating in a bath of ice water, the temperature can only be certain to be 32F AT the interface of ice and water. Everywhere else there can be a temperature gradient, and the way most temperature probes are insulated with plastic/rubber, it would be nearly impossible to ensure that it is truly reading 32F. What I did is I calibrated my digital thermometer in ice water, then calibrated my temperature probe against the digital thermometer at room temperature, since the nonlinearity of an NTC probe makes it hard to be accurate across a large range of temperatures. Even then, I would only say this method is accurate to +-2F, as the temperature I read with my digital thermometer will vary each time from 30-31F to 33-34F (it's a $20 CDN thermometer, so not the most accurate I'm sure, but I don't care to spend more on a thermometer).

Because I have my doubts about the accuracy of calibration, I believe that people who ferment in a temperature controlled environment are probably almost always only within a 5 degree window, especially given the temperature gradients in the beer itself, since it is impossible to maintain uniform temperatures across the entire vessel without stirring the beer/wort continuously, which we obviously can't do.

Therefore, I personally believe that the results of brulosopher's exbeeriments are probably accurate. Most of the small details people nitpick over on forums probably do not make as big of a difference as one's own confirmation bias would lead them to believe, but this is a hobby, so we find it fun to perfect every last detail in the process. Additionally, fermentation control IMO is more about having peace of mind that your beer will remain in a safe range, without ever having to keep it in an ice bath or use a swamp cooler.

 

[m00ps]

Id also point out that the rest of the techniques used to brew those side-by-side beers were sound. The only difference was the fermentation temperature. The mash, pitch rate, sanitation, water chemistry, etc were all on point. Most homebrewers ascend a learning curve. By the time they get temp control, theyve definitely improved upon all other aspects of brewing as well

 

[DurtyChemist]

I can point you to scientific labs in universities all across the country that grow their yeast in temperature controlled environments if that's good enough. They aren't doing it as a hobby. They're doing it as research for many different things.

Temp control may not be distinguishable to the beer drinker but imagine living in a house that has temperature changes of 10 degrees with no control over the temp or ability to warm/cool yourself.

 

[Peruvian802]

Temp control may not be distinguishable to the beer drinker but imagine living in a house that has temperature changes of 10 degrees with no control over the temp or ability to warm/cool yourself.

Happens all the time at my house. i.e. temps last night were in the 50s so the house dropped to the low 60s as the windows were open. Later this afternoon today it will be in the high 70s so the house will heat up to the low 70s. I can still live, thrive, procreate, etc. Further, this is a thread on whether the ferm. temps will noticeably alter the taste of beer, so what's your point?

 

[pvpeacock]

Before I could control fermentation temperatures, I made a half dozen beers that tasted fine and fermented at ambient termperatures of approximately 68-70 degrees. I then made a batch during a heat wave and the internal temperature using US-05 yeast hit 85 degrees. It was absolutely awful and undrinkable. It tasted like rocket fuel or gasoline. Even after letting it age for 6 months, it was still terrible. That's all I needed to learn that I needed to be able to control my fermentation temperatures and, at a minimum, keep them within a certain range (e.g. 60's for ales).

 

[Dcpcooks]

“When a problem arises, and it is not a contamination problem, the first place to look is the temperature of the beer throughout all phases of fermentation, from pitching through final conditioning. High or low temperatures affect the production of many off-flavor precursors at the beginning of fermentation. Temperature also affects the yeast’s ability to reduce many off-flavor compounds at the end of fermentation. Large, uncontrolled temperature swings produce poor results, especially when the batch sizes are small.”

Excerpt From: White & Jamil Zainasheff. “Yeast.” Brewers Publications, 2010. iBooks.
This material may be protected by copyright.

Check out this book on the iBooks Store: https://itun.es/us/BbALQ.l

 

[AnthonyUK]

I think some people would be surprised to see how far off their calibrations are for their temperature probes.

You are assuming everyone uses an NTC
It is one thing to get the temp wrong but if you pitch enough yeast into a well aerated wort it is amazing what you can get away with.
I know of commercial breweries that ferment ales at 25°c and you couldn't tell.
But, get the temp too high inconjunction with underpitching or sprinkled dried yeast and you are much more like to develop off flavours.

 

[55x11]

Id also point out that the rest of the techniques used to brew those side-by-side beers were sound. The only difference was the fermentation temperature. The mash, pitch rate, sanitation, water chemistry, etc were all on point. Most homebrewers ascend a learning curve. By the time they get temp control, theyve definitely improved upon all other aspects of brewing as well

m00ps is exactly right. In my opinion the brulosophy experiments are very impressive by showing that changing a single variable while the rest of parameters are "dialed in" will not have a huge effect on beer quality.
But once you start playing with multiple parameters (and many of us inadvertently do, especially in the beginning), the margin of "error" becomes very narrow.

In other words, (for example) if you under-pitch old yeast in under-aerated wort with questionable sanitation, and THEN add wild temperature swings, beer quality begins to suffer in a very noticeable way - whereas if you kept the temperature steady and in the right range the yeast could have recovered just fine.

 

[homebrewdad]

I'm a huge supporter of Brulosophy. I love what Marshall does over there, and I promote his efforts on an ongoing basis.

But I never agreed with this one. He tends to use very clean, forgiving strains of yeast in his beers.

Earlier this year, I split up a batch of Irish red ale using WLP004. Now, I did NOT fully control all variables like Marshall does - namely, I fermented 5.5 gallons in a temperature controlled (65 F) glass carboy, then split off 1.5 gallons into a two gallon plastic bucket, which got placed in my bathroom to ferment at ambient temps (70-74 F).

The difference was striking. Again, I didn't go to a full panel of testers (more lack of scientific controls), but of the couple of people who tried it, nobody had a problem picking out the ambient fermented beer (as in 100% of the four tasters picked out the warm ferment, and did so confidently and quickly). Way more harsh esters in both flavor and aroma in the ambient ferment.

Here's the writeup I did, for what it's worth.

 

[davidst]

I then made a batch during a heat wave and the internal temperature using US-05 yeast hit 85 degrees. It was absolutely awful and undrinkable. It tasted like rocket fuel or gasoline. Even after letting it age for 6 months, it was still terrible.

I had similar results at above 80 degrees. My first batch of beer, I put the hot pan into an ice bath and very quickly melted all my ice before it cooled down (I had a few beers at that point and didn't want to drive to the store), I tried for an hour to get the wort to cool down, but then got tired and just pitched the yeast when it was still in the high 80, near the end of the fermentation cycle my AC broke and I had a couple of days of 85 degree heat. That batch of beer is completely undrinkable, I've also allowed it to age for a few months just hoping the fusel esters would lessen, instead the hop bitterness and aroma has lessened, and now the taste is even worse. Later this week I'm just going to drain pour the rest of them. It only took one batch before I got a cool brewing bag to help a little with temperature control (don't have money for the beer fridge w/temperature control yet). Now I keep my temperatures between 66-70 and those minor swings don't seem to seriously affect the taste of my beer.

 

[hunter_le five]

Temperature control absolutely does make a difference. The difference between my beers fermented at room temperature and those after I set up my fermentation chamber was night and day.

How precise it needs to be is certainly debatable. For many strains, just keeping it somewhere within the recommended temp range is probably good enough.

For other strains, I would say even a 5°F shift absolutely makes a difference.

 

[DurtyChemist]

Happens all the time at my house. i.e. temps last night were in the 50s so the house dropped to the low 60s as the windows were open. Later this afternoon today it will be in the high 70s so the house will heat up to the low 70s. I can still live, thrive, procreate, etc. Further, this is a thread on whether the ferm. temps will noticeably alter the taste of beer, so what's your point?

My point is it works but it isn't ideal. If temperature swings like that were acceptable medical research wouldn't have strict SOPs and temperature control.

 

[55x11]

I'm a huge supporter of Brulosophy. I love what Marshall does over there, and I promote his efforts on an ongoing basis.

But I never agreed with this one. He tends to use very clean, forgiving strains of yeast in his beers.

Earlier this year, I split up a batch of Irish red ale using WLP004. Now, I did NOT fully control all variables like Marshall does - namely, I fermented 5.5 gallons in a temperature controlled (65 F) glass carboy, then split off 1.5 gallons into a two gallon plastic bucket, which got placed in my bathroom to ferment at ambient temps (70-74 F).

The difference was striking. Again, I didn't go to a full panel of testers (more lack of scientific controls), but of the couple of people who tried it, nobody had a problem picking out the ambient fermented beer (as in 100% of the four tasters picked out the warm ferment, and did so confidently and quickly). Way more harsh esters in both flavor and aroma in the ambient ferment.

Here's the writeup I did, for what it's worth.

What you say is similar to my own experience, probably less controlled than yours.

I do wonder about the early vs. late fermentation.
For example, I believe that if you fermented first 3-5 days at 65F for both beers, and then once fermentation slows down, took one beer into 75F, and left another at 65F, the difference would be not noticeable.

 

[chisena]

In my 5 years experience, 5F is not going to make a detectable difference. However, I cannot point you to scientific data. When you start pushing +/- 10F however, you start nearing the recommend ranges of many yeasts and will undoubtably change the final flavor profile depending on the specific yeast used.

 

[murphyslaw]

My take was similar to what others have suggested...that because his other practices are likely solid (pitching enough yeast, having the right nutrients, etc), it helps minimize the effect of poor temp control.

I think this applies to almost all of his experiments. Have any of them actually confirmed the commonly held beliefs? It seems like they all conclude that the thing being tested doesnt make a difference. Except for the trub experiment, which yielded an unexpected result (others have shown similar results on this one).

I just find it hard to believe that so much of the things he tests dont actually matter. Thats why i think its likely that good brewers just have more leeway.

 

[douglasbarbin]

My take was similar to what others have suggested...that because his other practices are likely solid (pitching enough yeast, having the right nutrients, etc), it helps minimize the effect of poor temp control.

I think this applies to almost all of his experiments. Have any of them actually confirmed the commonly held beliefs? It seems like they all conclude that the thing being tested doesnt make a difference. Except for the trub experiment, which yielded an unexpected result (others have shown similar results on this one).

I just find it hard to believe that so much of the things he tests dont actually matter. Thats why i think its likely that good brewers just have more leeway.

I think I can recall maybe one exbeeriment where the tasters were able to distinguish a difference where it was "statistically significant". I think it says a lot about how sound his brewing practices are (other than the variable being tested) and most people's inability to perceive differences in the resulting beers. It would be interesting to have a less-experienced brewer repeat the same exbeeriments. For example, a possible outcome might be that what would have otherwise been a very bad beer becomes decent because of temperature control, and the warm-fermented beer is still bad.

 

[FlyDoctor]

Temperature control absolutely does make a difference. The difference between my beers fermented at room temperature and those after I set up my fermentation chamber was night and day.

How precise it needs to be is certainly debatable. For many strains, just keeping it somewhere within the recommended temp range is probably good enough.

For other strains, I would say even a 5°F shift absolutely makes a difference.

I happen to agree - but how many other improvements in your brewing technique accompanied your move towards temp control? I know when I started monitoring and regulating temps during fermentation, it signaled and accompanied a general interest I improved yeast health - with starters based on targeted cell counts, and oxygen, and better recipes etc.

This summer I've had some issues with warm ferments (up to low 70's) and have to say, I was also non-plussed with the difference in my beer compare with those fermented in the mid to upper 60's. Again, these were perhaps forgivable strains like cal ale and British strains, but still - I think this is a situation where there are covariables that predict better beer - but isolating any one will not make a huge difference (e.g. Read freakonomics and the impact of parenting...)

 

[masaba]

My take was similar to what others have suggested...that because his other practices are likely solid (pitching enough yeast, having the right nutrients, etc), it helps minimize the effect of poor temp control.

I think this applies to almost all of his experiments. Have any of them actually confirmed the commonly held beliefs? It seems like they all conclude that the thing being tested doesnt make a difference. Except for the trub experiment, which yielded an unexpected result (others have shown similar results on this one).

I just find it hard to believe that so much of the things he tests dont actually matter. Thats why i think its likely that good brewers just have more leeway.

The only ones that I have seen where there was a statistically significant difference in the tasting panel were the ones where he altered the water chemistry (here is one example: http://brulosophy.com/2015/05/18/water-chemistry-pt-2-messing-with-minerals-exbeeriment-results/). This is an interesting result to me because most brewers don't mess with their water chemistry at all.

However, even though the tasters were able to tell the difference between the two beers, they were pretty evenly split on which they preferred. This tells me that there really is a whole lot of room for variance in making good, and even 'the best' beer.

 

[Peruvian802]

However, even though the tasters were able to tell the difference between the two beers, they were pretty evenly split on which they preferred. This tells me that there really is a whole lot of room for variance in making good, and even 'the best' beer.

I find this interesting in that personal preference goes such a long way in any "tasting".

Let's face it, most general beer drinkers would have told you 15-20 years ago that a sour beer was one that went bad.

 

[murphyslaw]

I think his panels usually include beer judges and other experienced homebrewers, which make his results even more surprising