Author Topic: Diacetyl Test  (Read 239 times)

Offline Humberto Pizarro

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Diacetyl Test
« on: July 10, 2019, 10:18:19 PM »
Hello everyone. Just had, hopefully a simple question.
On a Diacetyl test, I take 2 samples, one is heated to 160° for 20 min, then cooled down to the same temp as the the 2nd sample. The question is,

Is the Heated sample suppose to taste exactly the same as the non-heated sample?

I dont taste or smell the buttery flavor. But they are different. I know heating the sample is suppose to show how the beer ages, so to me the heated sample should be different.  Thanks for the help.

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Offline JT

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Re: Diacetyl Test
« Reply #1 on: July 10, 2019, 11:31:31 PM »
I have found them different as well.  Just look for that buttery defect. 

Offline EnkAMania

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Re: Diacetyl Test
« Reply #2 on: July 11, 2019, 04:17:18 PM »
When I was in an off flavor class at homebrew con, I didn't taste it either.  I did have a slimy feel to me.
Some day we'll look back on this and it will all seem funny

Offline hopfenundmalz

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Re: Diacetyl Test
« Reply #3 on: July 11, 2019, 04:36:17 PM »
When I was in an off flavor class at homebrew con, I didn't taste it either.  I did have a slimy feel to me.

I have a higher threshold than many, and the tell for me is the slickness.

It is said that about 20% of the population is blind to Diacetyl. If you fall into that category, it makes judging harder, but then you might enjoy a beer that others object to.
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Offline EnkAMania

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Re: Diacetyl Test
« Reply #4 on: July 11, 2019, 05:50:26 PM »
When I was in an off flavor class at homebrew con, I didn't taste it either.  I did have a slimy feel to me.

I have a higher threshold than many, and the tell for me is the slickness.

It is said that about 20% of the population is blind to Diacetyl. If you fall into that category, it makes judging harder, but then you might enjoy a beer that others object to.

This why my girlfriend is my taster.  :)
Some day we'll look back on this and it will all seem funny

Offline hopfenundmalz

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Re: Diacetyl Test
« Reply #5 on: July 11, 2019, 06:16:12 PM »
When I was in an off flavor class at homebrew con, I didn't taste it either.  I did have a slimy feel to me.

I have a higher threshold than many, and the tell for me is the slickness.

It is said that about 20% of the population is blind to Diacetyl. If you fall into that category, it makes judging harder, but then you might enjoy a beer that others object to.

This why my girlfriend is my taster.  :)

If I'm not sure I ask my wife, "taste any D?".
Jeff Rankert
Ann Arbor Brewers Guild
AHA Governing Committee
BJCP National
Home-brewing, not just a hobby, it is a lifestyle!

Offline Humberto Pizarro

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Re: Diacetyl Test
« Reply #6 on: July 11, 2019, 06:56:21 PM »
Haha! Thanks guys for the feedback!

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Offline ynotbrusum

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Re: Diacetyl Test
« Reply #7 on: July 11, 2019, 09:40:08 PM »
I work backwards from the slickness to the taste, as it is often a bit subtle to my palate.  I am not blind to it, but I have to really search when a paired judge finds it based on flavor alone.  That said, I have had judges in competition say they detect diacetyl and if I don't readily find it (since I am judging with them as well), I will ask a very experienced and diacetyl-sensitive judge (if present) to confirm.  Surprisingly, the initial judge is frequently picking up something other than diacetyl. 

I had a beer that was diacetyl charged that I brought to a club meeting for comment and the club member that holds an annual tasting class confirmed it and asked for a few bottles for use at the next tasting exam, which I provided (bottled off tap).  In the interim the diacetyl was re-absorbed, evidently, because the flaw was gone by the time the tasting exam was held.  Odd, but true.
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