Wheat AG - Buttery flavor.

Hey all!

I brewed my first AG wheat (Hank's Hefeweizen from midwest supplies) almost 3 months ago. It's been in bottles for a little over 2 months. I've already had a few through various stages of conditioning, hoping to see it get better, but I get a very strong buttery flavor and aroma. It's not undrinkable, but it's definitely not satisfying.

Here's the thing: I think I already know what I did wrong, but I want a more experienced opinion. It has to deal with a very wrong attempt at a protein rest.

I started out like I always do. I Got my mash water up to 166, I mash in and hit my temp of 154, which is exactly what I was aiming for. I let it sit for 90 mins, and then read in my instructions about a protein rest. I was a bit confused, since I'd never done a wheat or heard of a protein rest. The directions said to do a protein rest at 115-122 degrees (looking back, it definitely said to do this before the mash). Being the noob I am, I plopped my wort chiller in my "mash tun" (I BIAB with a sparge) and got the temp down to 115 and let it sit for 20 mins. I then put my bag in sparge water @ 182 degrees and hit my target of 170 right on the nose.

I boiled as normal, ferment was good, sanitation was as good as I usually am, so I'm pretty sure it's not infected. It's never shown any other signs of infection, either. Did bringing the temp down to 115 cause the buttery off flavor? If not, what could it be? It's diacetyl I'm smelling and tasting, right?

Thank you all!

Yup. That's diacetyl, but it wasn't caused by anything you did in the mash. I've got problems with it myself, especially in lighter flavored / body beers. What's helped me immensely is to really pay attention to fermentation temps. Make sure you're pitching within 10 degrees of your desired fermentation temp and preferably get that fermenter in a fridge with a temp controller. After vigorous fermentation is over, warm it back up to around 70F for a couple of days to make sure the yeast stays active and breaks down the diacetyl.

Surprisingly, I haven't found much difference in diacetyl production regardless of pitching rate (which many folks here will tell you is the other piece of the puzzle). I don't really do starters, but whether it's from a vial / smack pack or a healthy dose from a prior yeast cake, I haven't seen much of a difference at all.

Beardedterror said:

Hey all!

It's diacetyl I'm smelling and tasting, right?

Thank you all!

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Ding Ding Ding we have a winner!!

Below is from John Palmer from his How to brew book. How to Brew - By John Palmer - Common Off-Flavors


"Diacetyl is most often described as a butter or butterscotch flavor. Smell an unpopped bag of butter flavor microwave popcorn for a good example. It is desired to a degree in many ales, but in some styles (mainly lagers) and circumstances it is unwanted and may even take on rancid overtones. Diacetyl can be the result of the normal fermentation process or the result of a bacterial infection. Diacetyl is produced early in the fermentation cycle by the yeast and is gradually reassimilated towards the end of the fermentation. A brew that experiences a long lag time due to weak yeast or insufficient aeration will produce a lot of diacetyl before the main fermentation begins. In this case there is often more diacetyl than the yeast can consume at the end of fermentation and it can dominate the flavor of the beer."

Sounds like my batch of nut brown ale that ended up tasting like buttered movie popcorn. Not good.

In retrospect, I think I pitched the yeast before the wort was cool enough and/or let it get too warm during fermentation and/or racked to secondary too early (removing the majority of the yeast before they had a chance to break down the diacetyl).

A lot of brewers are letting their beers ferment out at about three weeks in the primary or more (much more for bigger beers) to make sure that the yeasts are re-consuming those more complex molecules (i.e. Diacetyl).

aiptasia said:

A lot of brewers are letting their beers ferment out at about three weeks in the primary or more (much more for bigger beers) to make sure that the yeasts are re-consuming those more complex molecules (i.e. Diacetyl).

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I agree, I have always done 3-4 week primary fermentations and I do not transfer out of the primary. Lager yeasts need to be brought back to the low 70's for a diacetyl rest but ale yeasts should not have too much of a problem with this!

I am leaning toward the quote from Palmer!

To the OP, do you have long lag times from pitch to active ferment?

Just wondering!

KevinW said:

To the OP, do you have long lag times from pitch to active ferment?

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I never have a long lag time. I usually pitch around 10 or 11pm and I'll go to bed. When I wake up at 5 to get ready for work, it's always showing signs of a good ferment.

For this particular beer, I kept it between 60-63 for the whole ferment. Should I have raised the temp up closer to 70 a few days before bottling? My gravity readings indicated that the beer was done, and I left it another week after getting stable readings. I've never had this kind of problem, so maybe it's just a one-time thing. Will this sort of thing get better with age? Or should I just plug and chug the whole batch as quickly as possible?