Diacetyl or Crystal?

[alcibiades]

I just sneak tasted my first all grain, a pacific pale ale, after a week and a half in the bottle.

Its pretty good, but there is a slight off flavor. It isnt "slippery on the tongue" and it doesnt quite taste like butterscotch, but it is a certain sweetness, almost like a mix between lightly burnt sugar and butterscotch. The off flavor is definitely prominent in the aroma, but it doesnt linger too much. All in all, I don't think I mind it; it's an interesting nuance, but I'm just wondering if it's diacetyl or crystal so I can know if my process is flawed.

Here is the recipe (i know, a lot of random grains in small amounts...I just kinda threw them in there):

Pacific Pale Ale – 7/20/09
9.5 Pale Malt
.5 crystal 60
.25 Aromatic
.25 Cara Vienne
.20 Crystal 80
.25 Victory
1 oz Cluster at 60, .5 at 15,.5 at 5
.25 Cascade at 40
.5 Czech Saaz at 15, .5 at 5
3.5g mash – 172 to 152
4 gallon sparge- 185 to 168
BIAB method
S-05 Yeast with Starter
70% efficiency
9.4SRM
5.75 Yield
OG 1.050
FG 1.016
Dry hopped with .3 oz cascade
8/4/09 bottled – FG 1.013

 

[dingleberg]

If you taste butter it is most likely diacetyl. It fermented for 2 weeks. What was the temperature of the ferment? Did you move it to a secondary too soon or did you do a secondary at all? Usually no need to do a secondary unless storing for an extended period. If you have continued problems with diacetyl you can always ramp the temp a couple of degrees for a day or two at the end of fermentation. The yeast will reabsorb the diacetyl.

 

[alcibiades]

I did one week in the secondary. I thought two weeks was enough fermentation because it was a relatively low original gravity. Fermentation temp was high, prob around 75.

I'm also thinking it might be hot-side aeration. Would that cause this type of sweet off flavor? WIth BIAB, there a couple times in the process when hot wort is splashing (when dripping from the bag, when combining mash wort with sparge wort, etc).

 

[Minky]

What do you mean by "172 to 152" after "3.5 g mash"?

 

[alcibiades]

dough in at 172 F with 70 F grain, so it gets down to 152 F for the mash. The 3.5 gallons is the amount of water I start with for the mash. Sorry, I guess I'm using my "note language."

 

[malkore]

ales really shouldn't need a diacetyl rest, since they ferment at temps that allow yeast to clean up the diacetyl.

I'd wager its just the young beer and crystal. give it time. Its only 3 weeks since brew day.

 

[dingleberg]

Fermenting at 75 for two weeks should clear all diacetyl. If it's a sweet off-flavor your detecting, it's more than likely the crystal malts. Also, HSA should not be present if the only splashing was caused by hot liquid dripping into the hot wort. You would need a more violent splashing where lots of O2 was being introduced into it. HSA usually will give a stale cardboard flavor which usually only shows up after long storage.