Weastcoast IPA

[monkey50187]

A friend and I had a conversation just this weekend about Westcoast IPAs and fermentation temperatures. He argued that Westcoast IPAs need a cooler starting temperature for two days at the beginning of fermentation and raise the temperature to finish the primary. My current understanding is that if temperatures are going to vary then the start should be warmer to encourage a strong start. Then drop the temperature to avoid unwanted flavors.

I am interested to hear others experiences or rationalization.

Thanks

 

[pfgonzo]

I'm with your friend, and so is Chris White of White Labs. In his book, Yeast (which everyone should read multiple times), he recommends starting fermentation off at a lower temperature, and then ramping it up 4-7F or so to "encourage full attenuation." The yeast take off pretty well, and will slow down or stop if you drop the temp on them before they're finished. All yeast work optimally at a higher temperature than is recommended for fermentation. We ferment lower than the yeast's optimum growth temp because they produce esters, fusels, etc at those higher temperatures and those aren't desirable.

Most of the esters/fusels and other less desireable compounds are produced early in fermentation. By waiting until 72 hours or so after active fermentation begins, you get the benefit of more late-stage activity (to avoid a stuck fermentation), and none of the drawbacks of fermenting at that high a temp the whole time.

 

[monkey50187]

This is just what I needed. Looks like I need to read another book. Thank you for the information.

 

[Yooper]

I'm with your friend, and so is Chris White of White Labs. In his book, Yeast (which everyone should read multiple times), he recommends starting fermentation off at a lower temperature, and then ramping it up 4-7F or so to "encourage full attenuation." The yeast take off pretty well, and will slow down or stop if you drop the temp on them before they're finished. All yeast work optimally at a higher temperature than is recommended for fermentation. We ferment lower than the yeast's optimum growth temp because they produce esters, fusels, etc at those higher temperatures and those aren't desirable.

Most of the esters/fusels and other less desireable compounds are produced early in fermentation. By waiting until 72 hours or so after active fermentation begins, you get the benefit of more late-stage activity (to avoid a stuck fermentation), and none of the drawbacks of fermenting at that high a temp the whole time.

I'm in the same camp. Not only do I start low, I may even pitch below fermentation temperature, and let the yeast and wort warm up to the proper temperature. Yeast hate being chilled- but they love getting warmer.

Starter warmer may encourage more yeast growth, but by the time fermentation gets going many of the esters and things like diacetyl are already formed. It's far better in my opinion to pitch more yeast at a temperature at or slightly below the desired (low end) fermentation temperature and let it rise. At the end of fermentation, raising a degree or two or even five would be great to make sure that the yeast fully attenuates.