Diacetyl with pilsner malt??

[Lando]

I have recently brewed several all, or almost all, pilsner malt beers in different styles and with different yeasts. I am picking up a flavor that may be diacetyl, but it doesn't come across with a buttery nose.... its more of an oil slick on the tounge feeling. I'm not sure how else to describe the taste and feel.

Is pilsner known to contribute or produce diacetyl when mashed?
I have experinced diacetyl with Ringwood yeast which is known for diacetyl production, but i am getting the same flavors in my regular IPA, pale and kolsch. They all seem to have that taste I was getting with Ringwood and that is one reason I think it is likely diacetyl.

Just trying to nail down what this could be. I would post the recipes, but the only common element in my brewing with these beers is the pilsner malt, water, star san foam in the kegs and the one flavor that is present in all of them.

Thanks for the input.

 

[rjwhite41]

How long a boil do you do?

 

[bullinachinashop]

^ Ditto
Diacetyl Rest?

 

[malkore]

are you doing a diacetyl rest? dunno how long you've been brewing but on a kolsch that's cooler fermenting, especially this time of year, the yeast could be slow to metabolize any diacetyl formed in fermentation.

i'd look at over all yeast health, pitch rates, etc. too. Its my understanding diacetyl comes from yeast doing their work, not the actual malts, mash or boil length.
I don't think the DMS 'creamed corn' would come across as just an oily mouthfeel.

 

[Yooper]

You've nailed diacetyl perfectly! In large quantities, it's buttery, butterscotch, or buttered popcorn tasting. In small quantities, it's an oily mouthfeel, or a slickness on the tongue or teeth. For my lagers, I'm always testing for diacetyl at the end of primary by concentrating on the feel on my tongue and teeth and looking for a slick or oily sensation.

As to why you've got diacteyl, that's usually a function of the yeast, not the type of malt used in the beer. It could be from a too-short contact time on the yeast cake in primary, or from using a highly flocculant yeast that fell out before finishing the "clean up" job.

It can also come from stressed yeast, like using liquid yeast and not making a starter, or from wildly fluctuation temperatures. Fermenting too cool and not raising the temp at the end for a diacetyl rest could also be responsibl.e

 

[Lando]

Boil length on all were 90 min.
The kolsch was fermented on the cool side 60-64F, smack pack stepped into a starter, primary for 4 weeks and then into the keg.

Same taste with the Pale, smack pack of 1056. No starter. 3 weeks primary. 2-3 weeks secondary w/dry hop and then kegged.
Same taste with Ringwood IPA, where it is expected, without doing a diacetyl rest, no starter, 3 weeks primary, 2-3 weeks seconday.
The IPA and pale were a split batch. 2.5 gallon each from the same brew session. Only the yeast and dry hop was different.

 

[Yooper]

Boil length on all were 90 min.
The kolsch was fermented on the cool side 60-64F, smack pack stepped into a starter, primary for 4 weeks and then into the keg.

Same taste with the Pale, smack pack of 1056. No starter. 3 weeks primary. 2-3 weeks secondary w/dry hop and then kegged.
Same taste with Ringwood IPA, where it is expected, without doing a diacetyl rest, no starter, 3 weeks primary, 2-3 weeks seconday.
The IPA and pale were a split batch. 2.5 gallon each from the same brew session. Only the yeast and dry hop was different.

I wonder if the starter on the kolsch was too small (or the ferment temperature wasn't high enough- which strain did you use?) and the lack of a starter in the other batches are what caused the diacetyl to not be cleaned up by the yeast. Yeast stress can cause diacetyl, even in strains that aren't as famous as ringwood for creating diacetyl.

 

[bullinachinashop]

Sounds like stressed yeast. Are you stepping up to correct amounts based on OG?

 

[Yooper]

Sounds like stressed yeast. Are you stepping up to correct amounts based on OG?

Another (not pleasant) thought- pedio infection tastes like diacetyl. Did you ever get a buttery beer at a bar that didn't clean their lines well? That could be an indicator of infection.

Why this just hit me- you're using different yeast strains that don't typically produce much diacetyl (except for the ringwood). It definitely could be from underpitching, but it could also be a pedio infection in your brewing gear. I'd take this opportunity to bleach bomb everything, and replace all plastic. I sure hope I'm wrong, but I'm thinking more and more that this is where we're leading because of the variances in the batches but the same diacetyl flavor.

 

[Lando]

Clorox here we come!
Hope that's not it though.

 

[Yooper]

Clorox here we come!
Hope that's not it though.

Yeah, me too! I just can't think of any other common threads, except perhaps stressed yeast. and even then, stressed yeast doesn't always present as diacteyl- often stressed yeast will present as band-aids, esters, phenols, etc.

 

[BrookdaleBrew]

I had this same issue with 2 beers recently. I believe the cause to be the fact that my brewery has gotten colder due to the the change in weather on top of the fact that I pitched yeast that probably wasn't as healthy as it should have been. I bottled at 3 weeks, which is normally fine, but since the ambient temp is around 62 and the yeast wasn't healthy to begin with, I was left with some diacetyl in my beer. I am using a space heater in my brewery now and am hoping a few more weeks at 70 will help clear up the problem in the bottle.

 

[SourHopHead]

I did a few Diacteyl tests last year. Let my beers ferment 2-3 days 65ish and the brought them up to 70-72 for 4-5 days. Took a sample and put it in a pint glass and tossed it in the microwave. I tried to heat it to 150 deg and then cooled it down. If you don't get any diacteyl you are good. I always had it with not making a starter or poor quality yeast. I always do a starter on my stir plate and will start doing cell counts to have a little fun. Even with Jamil's yeast calculator I still think I am under pitching since efficiency still kinda up and down. I would prefer a slight over pitch but it has drawbacks as well. Most recently my Cream Ale with Kolsch yeast and my IPA with 001 no Diacteyl present. Kinda help when my Fiancée can taste it better than I can.

I rushed one beer last year and when I opened the fermenter it was so buttery I almost got sick. Neighbor loved it, so he got it all.

 

[BrookdaleBrew]

It is my understanding that diacetyl is a normal byproduct of fermentation and will appear in all beers at some point throughout the process. You tend to have a problem with it in finished beers when the yeast flocs out before it can be reabsorbed. This can occur with unhealthy yeast, highly flocculent yeast or fermentations that happen at lower temps.