Diacetyl in APA with US-05

[MaxStout]

I brewed a pale ale, a slightly altered version of Yooper's house pale ale. The beer I made has a distinct--though not overpowering--diacetyl flavor.

I brewed a 2.5 gallon batch on the stove, BIAB.

RO water with about 1.5g each CaSO4 and CaCl2, and 20ml 10% phosphoric acid in the mash. Mashed 154 60 mins., then 60 min. boil. OG 1.056, 38 IBU.

Fresh packet US-05, rehydrated.

Fermented at 62-65 for just over 3 weeks, bumped up to upper 60s for a few days, then bottled after 27 days total in primary. Did not dry hop.

Stored bottles at 68-70 for just under 4 weeks, chilled a couple for 2 days and tasted. The diacetyl is there, but not enough to overpower the hops. It's sort of like an English ale, but with American hops. Drinkable, but a weird combination.

Not sure the cause of the diacetyl. US-05 is usually clean and I've brewed many beers with that yeast--never a problem with that. It could be an infection, but the diacetyl is not the "rancid butter" flavor characteristic of that. And the diacetyl flavor isn't getting stronger, nor am I seeing gushers when I open them. I am almost a fanatic about sanitation. I've replaced bottling buckets, tubing, etc.

It has been a couple weeks since I tried the first one and subsequent beers are about the same.

Am I missing something here? Anyone else experience something like this? I suppose I could let the remaining bottles age a few more weeks at room temp and try some later.

 

[scottballz]

Was your base malt pilsner? If so, you should have done a 90 min boil. It would have boiled off all of the diacetyl.

 

[MaxStout]

Was your base malt pilsner? If so, you should have done a 90 min boil. It would have boiled off all of the diacetyl.

No, base malt was 2-row.

The 90 min boil for pilsner is to remove DMS (dimethyl sulfide), which is an entirely different compound.

 

[riderkb]

Was your base malt pilsner? If so, you should have done a 90 min boil. It would have boiled off all of the diacetyl.

DMS and diacetyl are two different things.

 

[brew_ny]

US 05 is very clean for me not sure why it would do that and would like to know

 

[riderkb]

The salt and acid corrections seem heavy-handed for a small batch, but I don't see how that would cause diacetyl problems. You also didn't say how you oxygenated, but a full packet of yeast in a small batch wouldn't need much oxygen.

US-05 has only made a diacetyl problem for me when I have packaged too quickly. That doesnt seem like your problem, though.

Peddiococus makes a lot of diacetyl. A minor infection could show up that way without being sour or gushing.

 

[Natdavis777]

Looks like you gave the yeast plenty of time to clean up so the only thing I can deduce it to is a minor infection.

What was the hop bill out of curiosity?

 

[MaxStout]

It could be a minor infection. That's the only explanation that makes sense. Bottling bucket, autosiphon, tubing, etc., any of those could be a vector. I am very fastidious about cleaning and sanitation, but I have heard that sometimes a real stubborn "house bug" can come along. I need to rethink the sanitation thing.

Some more info:

The hops were Centennial, 1/3 oz. at 60, 15 and 5. I oxygenated with pure O2 through a 2-micron stone for about 60 sec. I boil the stone before each use and blow it out into Starsan immediately after each use.

My water (from Bru 'n Water): Ca 77, SO4 85, Cl 76.7 RA -42. I added phosphoric to lower pH about 0.2.

One thing about ferm temps--I observed the temps to range from about 62-65 during the day. At night, when the thermostat in the house is set lower, the beer may have dropped a few more degrees. But I have heard of people fermenting US-05 at 60 or even below with no problems, other than some fruity esters.

 

[PrinceOfThePoint]

But I have heard of people fermenting US-05 at 60 or even below with no problems, other than some fruity esters.

I am stumped by your diacetyl issue, but as someone with a lot of experience using US-50 at the far low end of the temperature range, I would bet it wasn't your temps

 

[scottballz]

DMS and diacetyl are two different things.

Crap!!! Sorry I got confused. Thank you for correcting me.

 

[Staticsouls]

The temps that you gave, were those wort temps or ambient air temps that the fermenter was in?

 

[Staticsouls]

The temps that you gave, were those wort temps or ambient air temps that the fermenter was in?

Dead thread good one