Acetaldehyde flaws in my brews... :(

General Homebrew Discussion
1

My last two brews have had a powerful Acetaldehyde flaw.

One, a british brown ale, appears to have gotten infected. There was some floating sediment in the bottles and they foamed up considerably upon opening. Interestingly they just smell of acetaldehyde and are not source or putrid. They don’t taste much like a brown ale alas.

The other, sadly an expensive Russian Imperial Stout, also is smelling very strongly of acetaldehyde. This one does not seem infected however. It’s been aging for about 3 months and the off flavor/smell just seems to be getting stronger. I used a huge starter and oxygenated as well as I could using a wine whip. Temps were maintained in the mid 60’s and fermentation was fully completed.

These were not sequential brews and the the in between beer came out just fine…

Any ideas where I might be getting this off flavor from? I’ve rigorously cleaned by bottling bucket hoses… Crossing my fingers as I’m about to bottle a very expensive NEIPA.

2

Since acetaldehyde can be caused by oxidation, I’m wondering if your in between beers were also bottled.  I’m not an acetaldehyde expert, but a little more info could be helpful to someone who is.

3

What yeast(s) did you use for the flawed and good beers?

4

The most distant was the RIS and I used WLP007 Dry English.  It doesn’t ‘seem’ infected other than the fact that the acetaldehyde seems to be increasing.  Didn’t notice it after a month, but it’s quite pronounced now at 2.5 months.

The in between beer was a NEIPA using a starter made from White Labs vault strain - London Fog

The last was the definitely infected British Brown Ale was S04.