Diacetyl rest??

[Brewer #404298]

Still learning a lot. Trying to sort out what is critical and what is nice to have. Tried to search for this, but did not find a direct answer. I mostly do brown ales, stouts and porters.

I have noticed my beer tastes better in the keg 3-4 days after racking. Am I (unknowingly) doing a diacetyl rest (I don't think I am since I have dropped the temp of the beer to 33 degrees)?

I read this online:

But the fermentation should still be “rested” at this temperature for two days to ensure proper diacetyl reduction. Many brewers make the mistake of quickly crashing the fermentation temperature following terminal gravity. Why not? The beer is done, people are thirsty, and there is no taste of diacetyl in the beer.

Or would it be better if I transferred to keg and left it sit at room temp for 3-4 days then cooled and carbonated? Or is it the carbonation now at serving pressure that is actually why the beer tastes better? Or should I leave it in the fermenter for 2-3 days post final gravity to "rest"?

 

[Herm brews]

I do not keg my beer, but I am a patient brewer who bottles. My standard practice is to leave brew in primary fermenter for 3 weeks, then bottle condition for at least a week before drinking. To this point, I have only ever produced ales, but I do have a Vienna Lager scheduled next. From what I have learned here, my patience essentially achieves the effect of a Diacetyl rest.

 

[Minbari]

Most ale yeast doesn't produce much diacytl, add the fact that you ferment @65+F, not usually an issue.

With lager yeast @ less than 52F, I would 100% do a D- rest. If you taste fake butter, you have diacytl

 

[Donoroto]

Fermentation can be thought of as having two steps: first, yeast converts sugars into alcohol. Second, yeast converts other byproducts (like diacetyl) of step 1 into things less offensive. Generally, step 2 takes about as long as step 1.

Your D-rest will be mostly ineffective at 33 F.

I suspect that what you are tasting is a combination of brighter flavor from carbonation and a mellowing of the hops profile that comes with aging about a week.

 

[HighVoltageMan!]

As Minbari already said, ales rarely need a d-rest. Typically when the fermentation has slowed or stopped, most brewers will leave ales set a couple days to “clean up”.

If you get into dry hopping, you can get butter from the fermentation becoming active again due to hop creep. This one can be a little more difficult to fix because you want to limit hop contact time to 3 days to avoid vegetal flavors and aromas.

The best thing to remember is not fix a problem you don’t have. You may never have a problem with diacetyl, but should have a butter or off flavor similar to butter, you will know how to tackle it.

I brew mostly lagers and some yeasts are prone to diacetyl. Then you can either raise the temperature just before the beer is done or add the enzyme ALDC. I add the enzyme, it’s way easier.

I believe Don is correct about the beer being brighter after carbonation. The beer pH drops due to carbonic acid formed during carbonation. The other thing to remember is that ales benefit from a lager rest just like lagers. It helps the beer mature well.

 

[GFHomebrew]

IF my memory serves me correct some English Yeast like the Boddington strain may actually produce more Diacytle in the fermentation this off flavour even being acceptable in small amounts in English Bitters and such.

I perform a D rest in all my fermentations (raise fermentation temperature to 20c ish) A to allow yeast to clean up this off flavour and B to finish off fermentation.

 

[HighVoltageMan!]

IF my memory serves me correct some English Yeast like the Boddington strain may actually produce more Diacytle in the fermentation this off flavour even being acceptable in small amounts in English Bitters and such.

Yes! Don't forget about the butter in a Czech pils. I personally hate that flavor, but to each his own.