Creamy flavour from WLP036 (Alt)

[kirkcaldybrewer]

Morning all,

So I brewed my third alt recently with WLP036 White labs' dusseldorf strain. It has ended up with a luxuriant, rich mouthfeel, which I would describe with the word: "creamy". Although pleasant, this is not what I associate with alt beer (and which is different from my previous alts, with similar malt bills/hops). So, I wondered if it's due to the yeast?

Has anyone else has encountered this particular taste with WLP036?

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Some details: this was my first time using WLP036, for which a grew a nice healthy starter (activity kicked off within 6 hours!).

Fermentation was at 17.8C (64F). After 7 days, I increased to 19C (66F) and left a further 12 days. Nominally, this was my "diacetyl rest", but prolonged due to a business trip.

At this point (19 days total), I noted FG of 1.014 (on the high side, but not unexpected as I had mashed higher than I wanted at 68C/154F).

I also tasted it and recorded a flavour, almost a sensation, I would describe as like a lingering fat flavour on the tongue. Reminiscent of milk.

Anyway, I proceeded to lager at 2-3C (36F) for a further 2 weeks and then kegged.

After this, I tasted again and still noted a milky sensation.

I concluded that I had a diacetyl problem. I haven't had this before, but it's usually described as 'butterscotch/butter' smell and this seemed close enough to 'milky'. So, I tried warming the keg back up to 20C for a further week to encourage the yeast to process the diacetyl.

After a week, I cooled the keg back down and I finally tasted it last night when I discovered the flavour/sensation had morphed into a pleasant creaminess.

 

[jdauria]

See #1 on this link https://learn.kegerator.com/off-flavors-in-beer/ It describes the various causes of diacetyl. I think you left the beer on the yeast cake long enough, so look at your boiling practice, did you have a good rolling boil? Or other option would be whether your oxygenated your wort.

 

[kirkcaldybrewer]

On the boil, you may be onto something...just prior to this batch, I upgraded from a 24L to a 60L pot and this was one of my first attempts at a full volume BIAB. One consequence is that the large volume of water led to a rather more gentle boil than normal. Perhaps this is telling me I need a more powerful burner?
I've read a bunch of things recently that claim DMS is not a problem with modern malt...but the proof is in the pudding...

 

[jdauria]

On the boil, you may be onto something...just prior to this batch, I upgraded from a 24L to a 60L pot and this was one of my first attempts at a full volume BIAB. One consequence is that the large volume of water led to a rather more gentle boil than normal. Perhaps this is telling me I need a more powerful burner?
I've read a bunch of things recently that claim DMS is not a problem with modern malt...but the proof is in the pudding...

Are you brewing on a stove top or a propane burner? A full volume boil on a stove top can be an issue. During the winter when I brew inside I have to straddle my 60L kettle over two burners on my gas stove to get a moderate boil. Same pot on propane burner, with full batch BIAB,no problem with a good rolling boil.

DMS is different than diacetyl. DMS is more of a cooked corn off flavor that you can get from lighter malts like pilsner. You will see that most recipes that call for a large grain bill of pils will call for 90 min boil to help drive off the DMS precursors. The other key to prevent it is not boiling with the pot covered.

 

[kirkcaldybrewer]

I'm brewing outside with a propane burner. It's 8.5kW, so much more than a stove top. It still took an hour to get my total water load (33L) to mash temp, and then further 45 mins to reach (insipid) boil. Ambient temp was around 3C, which didn't help. I boiled with the lid off.

However, it was pilsner malt and I only did 60 min boil. Man! Had been reading so much beforehand about how DMS is a non-issue with modern malt (see e.g. the brulosophy 30 min boil experiment!) Well, live and learn.