Slick/ oily mouthfeel... diacetyl?

Does the below sound like diacetyl or something else? I'm not aware of any chemicals common in beer that cause an oily mouthfeel. Discuss?

Problem:
Beer tastes good (no detectable butter flavor), but has a somewhat unpleasant slick/oily mouthfeel that lingers.

Knowns:
First AG.

Biermunchers centennial blonde.

Brewed 1-19. Racked to keg 2-09.

Mashed a bit high (159 F).

Ended up with WAY less wort than intended into fermenter, added unboiled tap water.

Stirred up some trub and had some issues with the hose sealing to the racking cane (fixed), so definitely aerated the beer (oops!).

Cold crashed for a few days prior to racking.

Fermentation temp was 60-70F. Took approximately 36 hours to show signs of fermentation after pitching.

No signs of infection.

Keg lubed prior to filling with silicone faucet lube. May have went overboard. Don't THINK this is the issue, I'd imagine that a LOT would be necessary to cause this level of oily mouthfeel.

Hypothesis:
I've got diacetyl.

Further discussion:
I may do the up to 140, hold for hour, see if there's a butter taste. While I'll certainly finish this beer, I'd like to avoid this in the future. I may also try pulling the keg and letting it sit for a week at room temperature. That will, however, leave me without a session beer.

As far as I know, an excess of diacetyl can make for an oily mouthfeel. Which yeast did you use?

Nottingham

I recently had the same comment re: slick and oily not only in the mouthfeel but also noticable on the head/and lack of head retention in my Oatmeal stout. The judges hammered me for sanitation and oxidation...
I personally thought it was the oats and too much starsan foam. I know, I know don't fear the foam, but sometimes it looks like it makes a slick ontop of the beer.

Ya know - this is actually the first beer that I used starsan on, though then again, I've bottled previous beers with starsan foam in them and had no issues. I've tasted full strength starsan - and didn't notice an oily texture.

I should also mention that this brew isn't as clear as it should be (not a heffe), and there was a fair amount of trub in the carboy due to poor racking technique

I have a second batch of the beer waiting in primary for a keg - hopefully the second batch doesn't have the "greasy" issues. Other than the mouthfeel - I really dig this beer as a session brew.

What was the recipe?

Yeah. i'm not really balaming starsan for my issue, just mereley pointing out the fact thet starsan bubbles degrage into a "slick" after i rack. The Oatstout was the first "oily" mouthfeel in a beer and I've used starsan exclusively for the last 15 batches.
Originally I thought the slickness was within style for an oatstout (i guess some is but not the ammount i had) but it got worse over time, so I think it was poor sanatization coupled with oxidation....

Yeah, my first thought was flaked oats. What's the grain bill for BM's beer?

So any ideas other than diacetyl? Obviously there were no oats...

I'm not sure why you need another reason other than diacetyl. When I hear "slick/oily" mouthfeel my automatic conclusion is diacetyl. Period. Unless you a. added olive oil to the beer or b. mis labeled the trait.

Oatmeal does have a definite effect on mouthfeel but it is not oily. I've never even heard it described as oily. It is just a thick pleasing weight. Almost universally pleasant. Diacetyl otoh when bad enough to get oily is a terrible experience. Nasty pervasive, mouth-stainingly (hard to wash out) so.

On the other other hand, I have heard of infections that have this effect, I just have not ever experienced it in a bottle to be able to identify it.

Edit: Oh yeah, Since star-san is an acid it would have the exact opposite of oily for mouthfeel. It would feel astringent if anything.

Diacetyl will give you a buttery popcorn flavor/aroma.

brewboy5150 said:

Diacetyl will give you a buttery popcorn flavor/aroma.

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That would be a good thing. YOu could sell it as snack and a beer in a bottle. No, Diacetyl offers up a butter nose and taste when it is in small quantities, go overboard and you get a very unctious oily taste and mouthfeel.

The popcorn would have to come from DMS. So maybe if you combine the two you could get a nice snack.

See - the reason I was asking if it could be something else is that MY PALATE doesn't detect any butter flavors. Doesn't mean they aren't there, but I just don't taste em.

My understanding was that if diacetyl (why do I want to spell it diatcetyl?) was present to the point that you'd feel it, the butter flavor would be overwhelming.

Nonetheless, I'll pull the keg and let it sit at room temp for roughly a week if the oily mouthfeel is still there when I pull a pint tomorrow (haven't touched it for 3 days). If it's diatcyl, that week should clear it up...

I've noticed diacetyl before without noticing butter. It was present as an oiliness, or a slickness on the tongue. It was definitely diacetyl, and that sounds like what you're experiencing, too.

See, I was waiting for Yooper to weigh in on this matter. She has forgotten more about diacetyl than I will ever know.

I think she also makes a lot of lagers which is where you're more likely to run into it.

As far as your plan to bring the temp up, sounds good. May not completely rid the beer of the off flavor but it certainly should help. I would do 72 hours at 70o.

No off flavors, just the oily mouthfeel.

Thanks yoop for the reply - that's exactly the reply I was looking for. I tend to over think those things I don't know.

So what happened? Were you able to clear up that diacetyl?

I'll pull a drink off that keg tonight and report back. It's warm (current setup only allows 1 keg... working on that...), but I'm curious too!

I've noticed this on a few of the beers I've done since I moved to Florida. The water is really soft here...do you think that could have something to do with the "slick" mouthfeel?

curtis97322 said:

I'll pull a drink off that keg tonight and report back. It's warm (current setup only allows 1 keg... working on that...), but I'm curious too!

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So, did keeping it warm for several weeks clear things up? I have 5 gallons of a brew with a buttery taste and slick mouthfeel. That brew was a disaster from the start, but I'd like to salvage it if I can. I'm worried that since I racked it off the yeast cake, there won't be enough yeast in the keg to clean up the diacetyl... but I'm hopeful.

It's BETTER. I still detect a level of diatcyl, but now it's quite drinkable. Actually - now it's GOOD and I wouldn't complain if it was served to me at a bar.

It would probably completely clear up if the ambient temperature was warmer (~60 in the house) and if I hadn't cold crashed (clearing most of the yeast out). I think part of my issue was a little bit of disturbed trub (had to move from fridge to shelf - didn't do so as gently as I meant to). The beer was cloudy back when it had the weird mouthfeel - now it's nice and clear.

Time heals all things beer...

Once primary fermentation is complete I think that you are stuck with the diactyl, unless you krausen. The point of warming your beer up to the mid sixties is to encourage the yeast that is still active to metabolize the diactyl. If you have finished fermentation and the yeast have gone to sleep there is no way to wake them back up other than adding some actively fermenting wort to use the stuff up.

anderj said:

Once primary fermentation is complete I think that you are stuck with the diactyl, unless you krausen. The point of warming your beer up to the mid sixties is to encourage the yeast that is still active to metabolize the diactyl. If you have finished fermentation and the yeast have gone to sleep there is no way to wake them back up other than adding some actively fermenting wort to use the stuff up.

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Reviving this old thread because it looks like I have a diacetyl problem.

I made a honey pale ale recently and sampled the first bottle after only 5 days of conditioning and it had a definite slick mouthfeel.

It was an extract recipe as below:

6.3 lbs light LME
1.5 lbs 20L crystal Malt
12 oz natural Honey
Bittering Hops 1 oz sterling pellets 60 minutes
Flavoring 1 oz cascade whole leaf 10 minutes
Aroma 1 oz cascade whole hops at flameout

Steeped crystal malt 20 minutes at 155
Added LME at start of 60 minute boil
Added Honey at flameout
Pitched Notty dry directly into wort at about 72 degrees.
Star sans for sterilization.
Primed with 2/3 cup cane sugar

A few notes about the batch that was a bit of a disaster from the start. I didn't have a sterilized stainer when it was time to rack to primary so I decided to just let the whole hops go into the primary, but they kept clogging the funnel so I had to pour a little, set down the brew pot take the funnel out and carry it 20 feet to the garbage can and shake it out put funnel back in carboy (this is all in my garage which is not a clean environment at all). Finally after dumping the funnel out 5 times or so I went and got a clean chopspick from the kitchen and soaked it is starsans for 30 seconds or so then, whenever the funnel clogged with hops I just used the chopstick to poke them through into the carboy. So basically the process of racking to the primary took like 25 minutes and was very suboptimal.

Another strange thing was the honey itself. Rather than being a golden syrup it was a semicrystaline white solid even at 75 degree room temp so it was hard to get it out of the jar. I think I actually dipped the jar into the wort to get some inside to disolve the residue I couldnt scoop out with a spoon. The wort was just at flameout though so definitely at 200 degrees anyway. The last issue was the Notty got a very slow start and low krausen and I had airlock activity for a full 2 weeks or so.

I bottled after 3 weeks, one week after airlock activity stopped and I did check a FG which was 1.010(but not an OG, I was lucky just to get the wort in the carboy). I probably should have let it sit another week on the yeast but you know how impatience gets the best of us sometimes.

When I tasted the hydro sample it wasn't bad. Maybe a little sour, but not out of line with green yeast filled flat beer, but no oily mouthfeel. The reason I sampled a beer after only 5 days was because when I looked at it I noticed this bottle was not completely airtight with bubbles rising up the side. It was a fliptop bottle but I was one gasket short so I used 3 rubber seals from new bottle caps hoping that would work but it clearly wasn't airtight.

When I sampled that bottle at only 5 days it was actually already partially carbonated. It was quite cloudy, especially the lower half of the bottle, and all the bottles of this batch have a much larger than average tan sediment. Flavor was not bad, no significant sourness, no butter flavor or smell at all, but a definite heavy oily mouthfeel.

My frist thought was maybe the honey actually had a lot of wax still in it and that was the mouthfeel. Then I thought that my ratio of crystal to LME was way too high and that was what was giving this mouthfeel, I was hoping that the .75 lbs of honey would dry it out and balance the CM. I was fooled into thinking it wasn't diacetyl because of the lack of butter characteristics but now having read this and other threads it seems like it is much more common to just get the oil-mouth without the butter so it seems pretty obvious that what I have is diacetyl.

I guess my question is will it likely improve with longer bottle conditioning. My plan is to wait a full 3 weeks in bottle until trying the next one. I actually was able to drink the "oily" bottle by mixing it hlaf and half with some SN Cellebration ale and it was actually quite drinkable tha way so if it doesn't get better I will probably use it as a mixer, but I would sure hope to avoid it in the future.

One additional note I thought of, I did notice that the Hydro sample on bottling day was partially carbonated and I was really just thinking about taste, not mouthfeel so it is quite possible it was already oily feeling but I just missed it since I only took a single sip.