Diacetyl Production

I have a brew brain teaser (at least to me) and could use your help figuring this out.

I had a double brew day the other day and brewed two batches of beer with completely different recipes. one a pale ale with store bought hops and one a red ale with some homegrown fresh hops. I made five gallons of each, made a one gallon starter of Wyeast 1335 at 1.04 and pitched a half gallon into each batch. I have them sitting side by side fermenting together.

Initial fermentation temperature was a bit low at 61°F then after about ten days I raised it to 70F for 24 hours. I then recooled them down to about 65F where they are sitting now at day 13. I tasted each one today and to my surprise the pale ale had a strong diacetyl flavor/aroma while the red ale had no detectable diacetyl and a nice fruity aroma.

Now i realize that the pale ale probably just needs another D-rest, which I will do accordingly, but my question is why would these two beers, brewed in the same exact way (minus the specialty grain differences), be so different in flavor and aroma?

Here is the recipe for each:

Pale Ale
91% Pale Ale Malt
9% Biscuit
N. Brewer Hops 1oz ea @ 30min and 10min

Red Ale
8% Caraaroma
8% Victory
84% Pale Ale Malt
5 oz fresh hops split evenly @ 60, 10, and 5

I think they are just each on their own time table. Every fermentation is different even with the same yeast strain. Maybe the PA just needed another 24 hrs at 70F, maybe those specialty grains in the Red provided the yeast with an extra nutrient boost that the PA didn't have...

Could also be a bit of pedio in the one batch producing diacetyl.

wonderbread23 said:

Could also be a bit of pedio in the one batch producing diacetyl.

Click to expand...

Not after 13 days.


I wouldn't worry about diacetyl at this point. It could just be that the hops in the red ale are masquerading what the yeast haven't cleaned up in either beer. Warm it up a bit before bottling and keep bottles above 70F for a few weeks and it should go away.