Yeast starter temperature spike

[jbuckhead]

I tried my first starter the other day and not sure if a couple of problems along the way are anything to worry about. I did a one liter, 1.040 wort. Pitched in evening when it was cool and maintained a temp of around 73 degrees (5 above my primary ferm temp) for the first 14 hours. I checked again about 6 hours later and the ambient temp spiked to around 83 degrees. I took temp of starter and it was also 83 degrees. In a panic, I rapidly cooled it to around 75 degrees and let it slowly sit there as the ambient temp was dropping. The next morning (36 hours into fermentation) there was a 3/8" cake at the bottom of the bottle. I moved starter to fridge to hold until ready to use in the next couple of days.

Question 1: was the short-term temp spike long enough to develop off flavors?
Question 2: is the rapid cooling going to have a long term effect when I do the main batch of beer?


Johnny B

 

[WoodlandBrew]

Yes, it probably was long enough at the right time for the yeast to produce a noticeable amount of esters and phenol compounds. Rapidly droping the temperature will also cause the yeast to do a "toxic dump" in order to attempt to keep up with their environment. This has to do with the equilibrium that the yeast cells establish and the different temperature ranges that the enzymes in the yeast work best at.

To keep the off flavors out of your beer crash and decant the starter.

 

[jbuckhead]

Good deal. Thanks for the advice.


Johnny B