Best way to do a Diacetyl Test?

[haeffnkr]

Hello,
I had made a butter bomb Kolsch, brought it to my local HB club un aware of what I had. It had a slight off taste to it but I thought it was because it was green beer (only 13 days old....) I was then told that this was butter bomb and started to read up on diacetyl.

I had it keg carbed and all, I put it back in a fermenter with a big starter that was at high Krausen.
I have had it in there since Thur morning.
The beer is clear, not much going on, I lost a FG point (now at 1.010) from my original reading....Last night I pulled a sample and microwaved it a bit and it smelled BAD a little better than before I put it back in the fermenter...but bad....I did not taste it.
I then microwaved 2 other beers out of my kegerator, in a small glass, covered in clear plastic wrap for 15 seconds. Both of them smelled horrible also, but these beers taste great as others have said. Mind you these are a light blonde ale and very light cream ale...so there is no where for off flavors to hide.
All beers above made with WLP029 yeast, all grain, fermented at 62 and ramped up to 70 over a week or so and stayed at 70 for few more days/week. Then secondaried, crashed cooled and carbed in a keg.

So... that all said.
Am I doing the test right? Some say water bath? Smell and taste the beer after it cools off ? Some say microwave and smell?
Do all my beers have the Diacetyl precursor or am I doing this all wrong.

thanks for you help
Kevin

 

[duboman]

Wow! If anything after all these transfers of finished beer I would thin oxidation is now going to become your biggest issue!

Read this regarding off flavors and diacetyl:
http://www.kroc.org/Links/TroubleshootingGuide.htm

Good luck

 

[haeffnkr]

Thanks for the link but I dont see a recommended way to do a Diacetyl test.
Any other suggestions?

thanks Kevin

 

[patrick524]

There's a Diacetyl Force test which test whether or not you have diacetyl in your brew. I got this from "Yeast" by Jamil Zainasheff and Chris White
Materials
Two Glasses
Aluminum Foil
Hot Water Bath
Ice Water Bath
Thermometer

Procedure
1. Heat the water bath to 140-160F
2. Collect beer in each glass and cover with aluminum foil
3. Place one glass in hot water bath, while keeping the other at room temperature
4. After 10-20 minutes remove beer from hot bath and cool to the same temperature as the other sample (use the ice water bath for this)
5. Remove the aluminum foil from both samples and smell each sample. If you smell the buttery character of diacetyl in either or both samples, your beer has the diacetyl precursor

Okay so if the heated beer has the smell but the room temp beer doesn't-keep the beer on the yeast.
If both have the smell then the beer will need more time on the yeast, you could also do a diacetyl rest on your brew by raising the temp of the beer by 10 degrees for 48 hours.
I haven't had a chance to try this. Let me know if this helps!!
If you've already kegged it and have moved it off the yeast-you're out of luck, I think...

 

[duboman]

Thanks for the link but I dont see a recommended way to do a Diacetyl test.
Any other suggestions?

thanks Kevin

The link was provided so you can read up on it and figure out how you can go about eliminating it a a concern with your process an set up, then you won't have to worry about testing for it

If it is already present in the finished beer it might age out and it might not but continuing to transfer and already kegged and carbonated beer is only going to cause you other problems and trash the entire batch.

 

[haeffnkr]

Thanks for the links and tips.
I get the point, I should try and change my practice to eliminate all possible challenges.

Next brew I will try to Primary ( a little longer) crash cool, then rack to keg with gelatin and that should eliminate the oxidation/diacetyl/infection chances.
I want the clean taste of a secondaried beer, but not do a secondary
Trying rack out of the primary just after the yeast has cleaned up things, but not too soon, is an art I guess.

thanks Kevin

 

[Yooper]

One thing interesting to note is that some people are unable to detect or taste diacetyl at all. So, you may not be able to taste it while I could find a butter bomb. That doesn't help much, I guess, but I'd suggest doing Palmer's diacetyl test (as outlined in howtobrew.com) and having a friend with you to see if he/she can taste it.

What might help is that in very small amounts, diacetyl presents like a slick or oily mouthfeel. It can be a slick feeling on the teeth, or a slight oiliness on the tongue. With some lagering, that little bit of diacetyl can get much worse, and become a butterbomb. So if you ever notice an oiliness in a beer, that's diacetyl.