fearing diacetyl

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ejf063

ejf063

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Hi all,
I am brand new to this. I have searched the threads and I am still confused at my issue. I have just kegged my first batch of Brewer's Best American Pale Ale. The fermentation in the primary went for about 3 weeks at 64-66 degrees. I transferred to a secondary where it sat at the same temp for another 3 weeks. I tasted the beer after having forced CO2'ed it and I have a hint of butterscotch at the end. I don’t know what I did wrong. I have been told that secondary is not necessary for ales. I was also told to let the initial fermentation slow (about 1-2 bubbles per minute), then take the batch to a warmer climate (~71 degrees) for 24 hours, then back to 66 degrees. I have my second batch in a primary now, an Alpha King extract clone. I brewed it Saturday, 2/16 and I am still getting 3-5 bubbles per minute (2/18). I don’t want to ruin this next batch. How can I control the Diacetyl. Should I taste the beer, should I leave it alone, should I raise the temp? Any help would be greatly appreciated. Thanks!
 
Do you have a Revvy Bubble Counter (RBC) you could replace your airlock with by chance? ;)

FluxCapacitor3947.jpg
 
Just kidding.....seriously, don't worry about "bubbles." They really have nothing to do with anything. There's YouTube videos of EMPTY carboys bubbling the airlock. Stop counting bubbles.

NOW, the diacetyl. First off, there's always diacetyl. It's naturally produced by yeast in ALL fermentations. They produce more diacetyl at warmer fermentation temps, less at cooler temps. So you just need to get your temps down a little bit, while keeping within the optimum temp range of whatever yeast you are using.

Remember that during fermentation, yeast are EXOTHERMIC, i.e., they produce heat. When you were fermenting at an ambient 64-66F temp, the FERMENTATION temp was actually 3-8F higher than that, so it was closer to 67-74F. That's on the high end of most ale yeast. You really should have started closer to 58-60F for a typical ale yeast, like S-05.

So at those slightly higher fermentation temps, your yeast produced more diacetyl.

The good news is that diacetyl is pretty easily conditioned out given time. It breaks down pretty quickly. The 6 week point you are at now is still a pretty young beer. Another 4-6 weeks of conditioning at room temp will break down that diacetyl. The idea behind that diacetyl rest your guys recommended (i.e., warming it up to 71) is actually to produce the diacetyl on purpose so it can go ahead and start breaking down. This most commonly used in the lager process, where the slow and low fermentation would result in the diacetyl precursers from ever changing to actual diacetyl until you warmed the beer up to bottle it. Instead, you go ahead and create the diacetyl in the beer earlier on so it can start to break down during the lagering process, saving weeks of conditioning time on the back end. Doing this diacetyl rest in your situation was pretty pointless, becuase you fermented high enough that the diacetyl was already present in the beer.

Sounds like you already have this one in a keg at fridge temps. Take the keg off gas and out of the kegorator, and let it sit at room temp for 4-6 weeks, and it will be fine.

Next time, ferment the beer at the lower end of the yeast's optimum temp range (assuming you have some form of temp control). Plan on active fermentation taking a few extra days, but a SLOWWWWWer fermentation is ALWAYS a CLEAAAANNNNer fermentation!

Good luck!
 
Wait.... I can unpressurize the beer without ruining it? Simply drain the co2 from the keg, re-rack to a carboy and allow it to sit? Seems like an easy enough fix but won't unpressurizing the beer effect the mouth feel and overall taste? I get that i am trying to get rid of the butterscoth. I guess I am just nervous about the overall changes that could take place. The upside is I could add some warrior hops I have left over for some dry-hopping. Anyway, thanks for the info. If u could address my concerns that would be great. Also, u got me on the RBC! Welcome new-guy! I almost placed an order. The is again for the help.
 
You don't want or need to unpressurize the keg at all. Leave it under pressure (you don't want oxygen in there, just CO2), just don't leave it on the CO2 tank. The change in temp won't adversely affect the beer, it'll just condition at a more reasonable rate at room temp than it will at serving temps. If you leave it at serving temps, it is going to take exponentially longer for the diacetyl to break down, like 4-5X longer.
 
That seems like it makes sense, but I've never once had any diacetyl issues go away with conditioning once the beer was lagered or bottled or kegged.

It's worth a try, but I don't know if it will work. Krausening would probably work, but I can't think of anything else that can reduce diacetyl at this point.
 
Well, what the heck. I will give this a shot. I'll disconnect, take it from the fridge, leave it pressurized and in the keg, and move it to a room temp. Should I add a little more pressure to the keg just to hold it? My pressure is at 8 now.
After about 3 weeks, I'll give it another taste test and post the results.
Now for my second batch: I took an additional thermometer and placed it next to the carboy. My sticky thermometer on the carboy says the temp is 66 degrees and the new thermometer says ~65. I obviously dont want diacetyl in this batch. So, the plan is to simply leave it in the primary for a total of 6 weeks. Should i rack this to a secodary to take the beer off the yeast cake, or will it be okay in the primary until keg time? I have read so many different opinoins....
Thanks for the help!
 
TopherM said:
Just kidding.....seriously, don't worry about "bubbles." They really have nothing to do with anything. There's YouTube videos of EMPTY carboys bubbling the airlock. Stop counting bubbles.

NOW, the diacetyl. First off, there's always diacetyl. It's naturally produced by yeast in ALL fermentations. They produce more diacetyl at warmer fermentation temps, less at cooler temps. So you just need to get your temps down a little bit, while keeping within the optimum temp range of whatever yeast you are using.

Remember that during fermentation, yeast are EXOTHERMIC, i.e., they produce heat. When you were fermenting at an ambient 64-66F temp, the FERMENTATION temp was actually 3-8F higher than that, so it was closer to 67-74F. That's on the high end of most ale yeast. You really should have started closer to 58-60F for a typical ale yeast, like S-05.

So at those slightly higher fermentation temps, your yeast produced more diacetyl.

The good news is that diacetyl is pretty easily conditioned out given time. It breaks down pretty quickly. The 6 week point you are at now is still a pretty young beer. Another 4-6 weeks of conditioning at room temp will break down that diacetyl. The idea behind that diacetyl rest your guys recommended (i.e., warming it up to 71) is actually to produce the diacetyl on purpose so it can go ahead and start breaking down. This most commonly used in the lager process, where the slow and low fermentation would result in the diacetyl precursers from ever changing to actual diacetyl until you warmed the beer up to bottle it. Instead, you go ahead and create the diacetyl in the beer earlier on so it can start to break down during the lagering process, saving weeks of conditioning time on the back end. Doing this diacetyl rest in your situation was pretty pointless, becuase you fermented high enough that the diacetyl was already present in the beer.

Sounds like you already have this one in a keg at fridge temps. Take the keg off gas and out of the kegorator, and let it sit at room temp for 4-6 weeks, and it will be fine.

Next time, ferment the beer at the lower end of the yeast's optimum temp range (assuming you have some form of temp control). Plan on active fermentation taking a few extra days, but a SLOWWWWWer fermentation is ALWAYS a CLEAAAANNNNer fermentation!

Good luck!
Click to expand...

Interesting. I always thought that the diacetyl rest was to break down already formed diacetyl. LOve this forum- learn something new every day!Thanks Topher.
 
ejf063 said:
Well, what the heck. I will give this a shot. I'll disconnect, take it from the fridge, leave it pressurized and in the keg, and move it to a room temp. Should I add a little more pressure to the keg just to hold it? My pressure is at 8 now.
After about 3 weeks, I'll give it another taste test and post the results.
Now for my second batch: I took an additional thermometer and placed it next to the carboy. My sticky thermometer on the carboy says the temp is 66 degrees and the new thermometer says ~65. I obviously dont want diacetyl in this batch. So, the plan is to simply leave it in the primary for a total of 6 weeks. Should i rack this to a secodary to take the beer off the yeast cake, or will it be okay in the primary until keg time? I have read so many different opinoins....
Thanks for the help!
Click to expand...

Six weeks in the fermenter? Wow, I"ve never done that. Let us know how it works out. I usually package about day 10-14 for almost all of my beers, except for lagers.
 
JimRausch said:
Interesting. I always thought that the diacetyl rest was to break down already formed diacetyl. LOve this forum- learn something new every day!Thanks Topher.
Click to expand...

Yes, that is indeed the point of the diacetyl rest. Diacetyl is formed by yeast as a byproduct of fermentation. When the active fermentation is over, the yeast are still trying to continue, so they'll start digesting less preferred foods such as maltiose. Then, they'll even go back and start digesting their own waste products (such as diacetyl).

Like I said, I never knew anybody who had any luck getting rid of diacetyl after lagering, or after packaging the beer except by krausening (to get active yeast to clean up the diacetyl). I hope I"m wrong, though, and you can do it.
 
ejf063 said:
Should I add a little more pressure to the keg just to hold it?
Click to expand...

NO! Pressure will increase as it warms up! Co2 will come out of solution and cause more pressure, so just leave it be!

And I agree with Yooper. If it was me, I'd either live with it or plan to krausen it.
 
Yooper said:
I usually package about day 10-14 for almost all of my beers, except for lagers.
Click to expand...
Just won 2nd and 3nd place in my local bjcp sanctioned brew comp for my 1st 2 lagers (dort export and munich dunkle). both went into kegs for lagering w/i 2 weeks. just adding to the point that there is no one right way to do something. Big pitch. No diacetyl at all.


I will add I am very sensitive to diacetyl as it showed up in two IIPA's back to back (possibly due to too warm of a pitch?). the 2nd one I did pitch a fresh starter into the finished beer in kegs as it was at high krausen. It reduced it somewhat but not to the level of fixing it.
 
tre9er said:
NO! Pressure will increase as it warms up! Co2 will come out of solution and cause more pressure, so just leave it be!

And I agree with Yooper. If it was me, I'd either live with it or plan to krausen it.
Click to expand...

Since this is my first batch I think I can try to recondition for a few days. So I won't add pressure and I won't bleed out the pressure that's already in there. Do I have to worry about flattening the beer?
 
ejf063 said:
Since this is my first batch I think I can try to recondition for a few days. So I won't add pressure and I won't bleed out the pressure that's already in there. Do I have to worry about flattening the beer?
Click to expand...

Ideally you'd keep it on pressure because yes, eventually the co2 in headspace will absorb but if it's fully carbed now and you don't off-gas at all, you're not "losing" anything.
 
tre9er said:
Ideally you'd keep it on pressure because yes, eventually the co2 in headspace will absorb but if it's fully carbed now and you don't off-gas at all, you're not "losing" anything.
Click to expand...

Great, thanks! I took her off last night, now I have to re-wait. :eek:
 
Make 1-1.5 quart starter with fresh yeast and pitch it at high krausen the whole thing. It will remove diacetyl. This is the only way I had luck with. Just sitting at room temperature will not do anything, your yeast is not active anymore and will not clean up.
 
UPDATE
After about a two week rest, both off the co2, and out of the fridge, I gave it another go. The beer didn't last a week. It still had a minor bit of butterscotch, but it was still very good.
Thanks for the update.
 

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