Start Warm then cool or start cool then warm

[ToastedPenguin]

I recall reading and possibly hearing on a podcast or two that for ales it can be good fermentation practice to cool the wort down to between ~75-80 (depending on the yeast), pitch the yeast and then slowly cool the wort down to the mid 60's.

After hearing/reading about this it made sense since the yeast slurry is room temp by the time I pitch it and at most times room temp is in the 70's so the yeast and wort are within 10 degrees of each other. I have been doing this myself for a while now and it seems to work fine with no ill affect, fermentation starts quickly and stays strong. By the time active fermentation is really going the wort is chilled to a more optimum temp.

However I have recently seen it mentioned a few times to do the opposite, cool the wort down to the mid 60's and then gradually warm it up to the upper range of a yeasts tolerance. Is this used to get a specific flavor profile from the yeast or is it just another way of doing things?

David

 

[GodsStepBrother]

I have always heard it is best to cool below your fermentation temperatures, then let it slowly rise. I am curious to see what others say on this subject.

 

[ArcaneXor]

Ah, the good old pitch warm/pitch cold debate. The truth is, both sides are right - it depends on how much yeast you are pitching.

If you pitch straight from a smackpack or vial, or sprinkle a dry yeast packet on top of the wort without rehydrating, you are introducing an insufficient number of yeast cells to the wort, meaning the yeast has a propagate extensively. That tends to happen more quickly when the wort is relatively warm. However, doing this will increase your odds of getting excessive esters, phenols and other flavor/aroma compounds that may be undesirable significantly, and it also increases the odds of a stuck ferment or underattenuated beer.

The preferred method is to maximize the amount of viable yeast pitched into the wort by making a large starter or rehydrating dry yeast, which means less propagation has to take place in the main batch. By starting cool, less esters etc. are produced. The fermentation is kept cold for 3 days or so before letting it slowly ramp up, which increases attenuation and serves as a diacetyl rest.

 

[Bensiff]

I tend to pitch a few degrees below fermentation temp then kick on the heat blanket to my desired temp which will take a few hours to hit allowing the yeast to "wake up." Once outside of the ester window (3 days or so) I start ramping temps to get the yeast motivated enough to give me a solid finish.

I know you can do it both ways, just like a lot of things in brewing, and you can probably make amazing beers by warm pitching that could never be made pitching cooler; however, I have done enough research to lead me to pitch at temp or slightly below. If an instance comes up that I need to pitch warm to get a desired effect then I wouldn't hesitate to do it.

 

[ToastedPenguin]

Thanks for the responses.

I realized that part of my "acceptance" of the warmer wort temp at pitch time (~75-80) is due to the time of year. I use starters for all my beers no matter the gravity and just adjust the size of the starter accordingly so the pitch rate is correct for the gravity. However since it can get quite difficult to chill the wort below ~75-80 during the summer months even with using a 50ft 1/2 inch immersion chiller, a pre-chiller sitting in an ice bath and whirlpooling, pitching on the warmer side has been the norm for warm months of the year.

But I have been investigating the idea of putting the fermenter(s) in my temp controlled chest freezer once I get to ~75-80 and allowing it to cool for a few more hours so it can get to ~65 before I pitch. I have just been so use to "cool quick, pitch quick before the bugs get at it" that I hadn't contemplated doing it that way. Any words of advice on the extended cooling method?

 

[ASantiago]

But I have been investigating the idea of putting the fermenter(s) in my temp controlled chest freezer once I get to ~75-80 and allowing it to cool for a few more hours so it can get to ~65 before I pitch. I have just been so use to "cool quick, pitch quick before the bugs get at it" that I hadn't contemplated doing it that way. Any words of advice on the extended cooling method?

That's what I do.

Others probably have a different take on it, but I believe it goes:

Cool down
Pitch cool
Warm up
Warm up some more after primary fermentation
Cool way down

 

[Catt22]

I have always heard it is best to cool below your fermentation temperatures, then let it slowly rise. I am curious to see what others say on this subject.

That's the way I do it. My thinking is that if you pitch on the warm side, you risk the yeast taking off like a rocket and possibly going volcanic. When that happens, it can be difficult to keep up with the heat generated by the yeast activity and get the wort cooled down to your desired fermentation temp quickly enough. It may well all be over before you do so. As usual, it all depends. It depends on a whole raft of variables such as how warm the wort is, the volume of wort, the cooling power of your fridge, freezer or fermentation chamber, blah..blah..blah. I don't think there is a one size fits all solution, but I'm with the cool start crowd. I like a nice slow and steady fermentation rate for the majority of my beers.

 

[terrapinj]

i was recently reading up on cold pitching which seems to be fairly popular for washed yeast

you cool wort about 4-5 deg below the lower threshold temp of the yeast and then pitch the yeast cold from the fridge

as the yeast wake up and get active they will raise the temp of the wort to the target range

if you cool the wort after fermentation begins you risk slowing the yeast down

 

[Cubslover]

Ah, the good old pitch warm/pitch cold debate. The truth is, both sides are right - it depends on how much yeast you are pitching.

If you pitch straight from a smackpack or vial, or sprinkle a dry yeast packet on top of the wort without rehydrating, you are introducing an insufficient number of yeast cells to the wort, meaning the yeast has a propagate extensively. That tends to happen more quickly when the wort is relatively warm. However, doing this will increase your odds of getting excessive esters, phenols and other flavor/aroma compounds that may be undesirable significantly, and it also increases the odds of a stuck ferment or underattenuated beer.

The preferred method is to maximize the amount of viable yeast pitched into the wort by making a large starter or rehydrating dry yeast, which means less propagation has to take place in the main batch. By starting cool, less esters etc. are produced. The fermentation is kept cold for 3 days or so before letting it slowly ramp up, which increases attenuation and serves as a diacetyl rest.

Good read here. Thanks!