Crap loads of acetylaldehyde in red ale with WLP004

[Mozz]

The Gravity has not dropped.
The aroma reminds me of my old mans wine cellar. True wog wine maker. Relied completely on the wild yeasts on the grapes for the ferment. He made some rough ones and a couple of decent ones over the years.

 

[MHB]

Personally I suspect its an infection - lots of bugs out there that like living in beer.
Other main causes are related to yeast, mainly yeast health, pitch rate and wort aeration.
One thing you could try is adding some more fresh wort, even a bit of D/LME in water to kick the ferment off again. Yeast can metabolise Aldehydes very effectively while it reproducing and will often reduce the total Aldehyde content very effectively.
Mark

 

[TheWiggman]

Mark raises a good point about the yeast (as he does), I've noticed you've got 2 x demijohns which I assume are 5l filled to about 4l. How did you go about starting them? Single vial into each at 1.040? Or two vials? Or did you step them up incrementally? The stepping up process is often the source of confusion/fault and easy enough to do wrongly.

 

[Mozz]

Yeast was 1 vial into 2L and grown using Shaking method. Cold crashed then stepped up to 2 x 3L and similarly grown out in 1040 LME. Should have given me a good pitch rate.
Was pretty careful with transfers etc (used to work as a microbiologist so my aseptic technique should be OK) but certainly doesn't mean I didn't get an infection at some point.

Mark I've already cold crashed and kegged. So not sure if what your saying is still an option?

Anyway the concensus seems to be an infection rather than a process problem.

I'll leave it age another 3 weeks and look back in on it.

 

[kaiserben]

On Saturday I pitched a 1.2L active starter of WLP004 into 1.048 wort at 18C. I had to move it out of the fridge 12 hours later and put it in an insulated cupboard, where the air temp was 22C on Sunday night. Air temp now steady at 21C.

So a fairly similar scenario to the OP.

My gravity has gone down to 1.013 (so far). It tastes good and I don't detect any acetylaldehyde. Maybe the slightest whiff of juicy fruit/bubblegum, but I don't get that when tasting, just some nice fruity esters. Plenty of yeast in suspension in the sample. It should still drop another couple of points and will clear up quite a bit before I package it up.

Sounds like OP just got unlucky with an infection.

 

[Mozz]

Well may have my answer. Travelling through Scotland as I write and making it my mission to try as many cask ales as possible. In the village of Applecross I had a red ale from the Isle of Skye Brewery and no shit it tastes pretty much exactly like my brew, with what I call a sasaparilla like flavour.
Not the flavour I was expecting but maybe that's just what it is. My wife likes it so I let her know there's at least another 50 L to get through at home.
The Skye Red won "Champion bitter of Scotland in 2013"