i've seen a lot of posts recently with the OP asking if his/her fermentation temps are too low. most of the time, their ambient temps are a bit low, but considering the exothermic properties of fermentation, they're actually fermenting right in the desired range for the yeast they're using. occasionally the OP is actually fermenting a few degrees below the manufacturer's suggested temp range. which, in my experience, is a vague guideline they set for 'optimum' yeast performance. i have some thoughts and experience on the subject of fermenting below recommended temps. by below i mean actual wort temps, and not ambient.
since very early on in my brewing, i learned the importance of fermenting any brew within the yeast strain's specified temperature range. i began controlling temps within my first ten batches by using what we home brewers call a 'swamp cooler', basically a large bucket containing a water bath for the FV. i started keeping temps in the middle of the range for the yeasts i was using, usually around 65-68 degrees, and man, did that make a huge difference in my beer right away. my ales were tasting like good ales right after FG was reached. i immediately realized the importance of temp control during active fermentation. i could primary the average ale for 2 weeks and have a beer that tasted great and was free of off flavors, something i struggled with in my first few batches.
as i brewed more and more great beer fermenting in the mid to upper 60's, i began paying more and more attention to pitch rates and the environment the yeast was working in, i.e. aeration, pitch temp, getting good breaks in the boil and when chilling wort, etc. i noticed that when i pitched the proper cell count into a well prepared and well aerated wort, my ales fermented fast and clean, even when the temps were a bit on the low side in my drafty, 89 year old house. so i started paying more attention to what other brewers said about fermenting ales at the low end or below the recommended temps and i came across an article in Zymurgy several issues ago that talked of just this. in split batches, using proper pitch rates in both, fermenting one in the middle of the temp range and one below the low end, the author produced two nice, clean ales. if anything, the cooler fermentation produced a cleaner, sometimes tastier brew. so i thought i'd have to do some experimenting in my own brewery.
i began with a yeast i'm quite familiar with, 1272, and planned a couple light beers, recipes i'd brewed before, using that yeast. in the past i'd fermented these beers starting in the mid 60's, and let them slowly rise to 68 or so by the end of fermentation, then held that temp for a couple weeks following stable FG readings. in the past, i'd had reasonably quick fermentations, FG reached in a week or so, with around 75% or so attenuation, and i got nice, clean, crisp pale ales with little to no fermentation flavors. now for trying these recipes at lower temps.
i decided with the first attempt, i'd let it it kick off at 58 degrees and slowly let it rise to 60-62 by the end of active fermentation, then hold temps there for the remainder of primary. the results were just as i expected. there was no noticeable difference in lag times, active fermentation lasted for 3 or so days, and FG was reached within a week. the surprise was that that first gravity sample tasted like a beer that had been in primary for weeks after FG was reached. it was clean, free of any yeast derived flavors (besides the taste of yeast in suspension) and it was even a bit more clear than i expected for such a young brew (especially one with 1272). i decided to stick with the plan and leave the beer in primary, as i normally do, for a week or two after stable FG readings. after three weeks, and a few days carbing in the keg, the resulting beer was one of the cleanest tasting pales i'd made to that point.
so with the next batch, same grain bill, mash and boil schedule, pitch rate, aeration, etc. (the hops were different, that's it), i decided to hold the entire fermentation 'below' the recommended temps. i kept it at 58 or so for the entire three week primary. everything went as it normally would for this particular beer, same lag time, FG reached within a week, gravity sample tasted clean and ready to go on day 7, etc. again, i let this beer ride for three weeks in primary, as i do with most ales. after a few days carbing and crashing in the keg, the results were impressive. the malt and hops flavors led the show. the beer seemed like one that had had time to condition and develop for some time, yet it was only days out of the fermenter. the beer was very clean, very crisp and had no detectable yeast derived flavors whatsoever. i was sold.
since then, except when brewing styles that benefit from warmer temps, i've chilled my wort and pitched below recommended temps, allowing the fermenting beer to come into the low end of the temp range for that yeast by the end of active fermentation. the results have been equally impressive as the experimental batches. one of my last brews was an English special bitter, an AG version of the Goldings Special Bitter in the current Zymurgy issue. i used Wy's 1318, the Boddington's strain. i pitched the yeast into 57 degree wort and held it there until fermentation started, which was about 5 hours from pitch. the activity quickly brought the wort to 61 degrees where i held it until the swirling and krausen seemed to hit it's peak and began to subside. then i slowly warmed it to 64 degrees where i held it til my first FG reading on day 6. it had gone from 1.052 to 1.012, 76.4% attenuation. the real treat, again, was how clean the gravity sample tasted. if i wasn't planning on dry hopping and bottle conditioning this batch, it would've gone into a keg the next day!
to sum up my feelings on the subject, many brewers leave their beer in primary for weeks or more after FG is stable to allow the yeast to clean up a bit. i'm one of those brewers. but, and this is a big but, i've noticed in these recent batches that there's not much, if anything for the yeast to clean up after FG is reached and my obvious next step is to see just how short of a primary i can do with these cooler fermented brews. my goal is that of many home brewers, to have a few recipes that i can turn around in under two weeks and have a fairly developed brew when the keg is tapped. nothing groundbreaking, i know, it's been done a lot. but it'll be a big step for me in my brewing to not have to wait months to go from grain to glass.
since very early on in my brewing, i learned the importance of fermenting any brew within the yeast strain's specified temperature range. i began controlling temps within my first ten batches by using what we home brewers call a 'swamp cooler', basically a large bucket containing a water bath for the FV. i started keeping temps in the middle of the range for the yeasts i was using, usually around 65-68 degrees, and man, did that make a huge difference in my beer right away. my ales were tasting like good ales right after FG was reached. i immediately realized the importance of temp control during active fermentation. i could primary the average ale for 2 weeks and have a beer that tasted great and was free of off flavors, something i struggled with in my first few batches.
as i brewed more and more great beer fermenting in the mid to upper 60's, i began paying more and more attention to pitch rates and the environment the yeast was working in, i.e. aeration, pitch temp, getting good breaks in the boil and when chilling wort, etc. i noticed that when i pitched the proper cell count into a well prepared and well aerated wort, my ales fermented fast and clean, even when the temps were a bit on the low side in my drafty, 89 year old house. so i started paying more attention to what other brewers said about fermenting ales at the low end or below the recommended temps and i came across an article in Zymurgy several issues ago that talked of just this. in split batches, using proper pitch rates in both, fermenting one in the middle of the temp range and one below the low end, the author produced two nice, clean ales. if anything, the cooler fermentation produced a cleaner, sometimes tastier brew. so i thought i'd have to do some experimenting in my own brewery.
i began with a yeast i'm quite familiar with, 1272, and planned a couple light beers, recipes i'd brewed before, using that yeast. in the past i'd fermented these beers starting in the mid 60's, and let them slowly rise to 68 or so by the end of fermentation, then held that temp for a couple weeks following stable FG readings. in the past, i'd had reasonably quick fermentations, FG reached in a week or so, with around 75% or so attenuation, and i got nice, clean, crisp pale ales with little to no fermentation flavors. now for trying these recipes at lower temps.
i decided with the first attempt, i'd let it it kick off at 58 degrees and slowly let it rise to 60-62 by the end of active fermentation, then hold temps there for the remainder of primary. the results were just as i expected. there was no noticeable difference in lag times, active fermentation lasted for 3 or so days, and FG was reached within a week. the surprise was that that first gravity sample tasted like a beer that had been in primary for weeks after FG was reached. it was clean, free of any yeast derived flavors (besides the taste of yeast in suspension) and it was even a bit more clear than i expected for such a young brew (especially one with 1272). i decided to stick with the plan and leave the beer in primary, as i normally do, for a week or two after stable FG readings. after three weeks, and a few days carbing in the keg, the resulting beer was one of the cleanest tasting pales i'd made to that point.
so with the next batch, same grain bill, mash and boil schedule, pitch rate, aeration, etc. (the hops were different, that's it), i decided to hold the entire fermentation 'below' the recommended temps. i kept it at 58 or so for the entire three week primary. everything went as it normally would for this particular beer, same lag time, FG reached within a week, gravity sample tasted clean and ready to go on day 7, etc. again, i let this beer ride for three weeks in primary, as i do with most ales. after a few days carbing and crashing in the keg, the results were impressive. the malt and hops flavors led the show. the beer seemed like one that had had time to condition and develop for some time, yet it was only days out of the fermenter. the beer was very clean, very crisp and had no detectable yeast derived flavors whatsoever. i was sold.
since then, except when brewing styles that benefit from warmer temps, i've chilled my wort and pitched below recommended temps, allowing the fermenting beer to come into the low end of the temp range for that yeast by the end of active fermentation. the results have been equally impressive as the experimental batches. one of my last brews was an English special bitter, an AG version of the Goldings Special Bitter in the current Zymurgy issue. i used Wy's 1318, the Boddington's strain. i pitched the yeast into 57 degree wort and held it there until fermentation started, which was about 5 hours from pitch. the activity quickly brought the wort to 61 degrees where i held it until the swirling and krausen seemed to hit it's peak and began to subside. then i slowly warmed it to 64 degrees where i held it til my first FG reading on day 6. it had gone from 1.052 to 1.012, 76.4% attenuation. the real treat, again, was how clean the gravity sample tasted. if i wasn't planning on dry hopping and bottle conditioning this batch, it would've gone into a keg the next day!
to sum up my feelings on the subject, many brewers leave their beer in primary for weeks or more after FG is stable to allow the yeast to clean up a bit. i'm one of those brewers. but, and this is a big but, i've noticed in these recent batches that there's not much, if anything for the yeast to clean up after FG is reached and my obvious next step is to see just how short of a primary i can do with these cooler fermented brews. my goal is that of many home brewers, to have a few recipes that i can turn around in under two weeks and have a fairly developed brew when the keg is tapped. nothing groundbreaking, i know, it's been done a lot. but it'll be a big step for me in my brewing to not have to wait months to go from grain to glass.
