Why Quick Start on Yeast Cake?

I brewed batch # 1 on 03/24, left it on the yeast at 42-44F for the last two weeks to clear. The beer was on the yeast cake (WLP530) for a month.

Today I brewed batch # 2. Transferred batch # 1 to the keg, put it back into the refrigerator, and worked on # 2. Same malt bill, hops, etc.

Due to an error on my part, the beer entering the carboy was about 83F. I hit it with O2 for about 60 seconds, and let it settle before putting it into the refrigerator.

Within 10 minutes of the 02, and approximately 20 minutes after transferring from the keggle, it began to start fermenting. I thought it was residual O2, or perhaps CO2 from the cake. Nope, it started fermenting.

Is this common for pitching on a cake, near immediate start. Lag time was 20 minutes or less.

This seems perfectly normal.

Did you use the entire cake for the next batch? If so, it is likely a pretty significant overpitch.

The higher start temperature probably had something to do with the quick start as well.

Yes, I pitched on the full yeast cake.

The OG of the first batch was 1.076, the second 1.085. Both are Raison D’Etre clones.

While it was pitched at 80F, it is now 72F.

At that gravity, pitching on the whole cake may not be a problem.

It is definately better to start below your fermentation temp than above it.

Fresh yeast cake and starting temp are the reasons for the quick start. I don’t see a quick start in itself being a problem though.

Lag time in fermentation is the time in which the colony of yeast builds up enough cells to tackle the job. Since you had more than enough yeast, this phase of fermentation was significantly reduced. The fact that you pitched at such a high temperature also lended itself to a faster fermentation. Pitching that high you’re probably going to notice a bit of fusels in your finished product.

I have found the WL530 to be a very active yeast. I like the Abbey yeast but have had monster blow offs and quick starts. I now start that yeast at 60F for about a week. Then raise the temp.