Brewing Yeast with John Palmer – BeerSmith Podcast #128

by Brad Smith on June 26, 2016 · 2 comments

PodNew200John Palmer joins me this week to discuss beer brewing yeast, the yeast life cycle and his upcoming new edition of “How to Brew” in a show recorded from the Homebrew Con 2016 show floor in Baltimore.

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Topics in This Week’s Episode (38:55)

  • Today on the show I welcome John Palmer, the author of How to Brew, Water and Brewing Classic Styles (Full Disclosure: Amazon Affiliate Links). John joins me on the show floor of Homebrew Con 2016 to discuss brewing yeast and the yeast life cycle.
  • We discuss John’s ongoing update to develop the “How to Brew” fourth edition of the book, which is planned for release next year, including John’s plans to update the book to take into account changes over hte last 10 years.
  • We start with an overview of the life cycle of a yeast cell and the stages of activity involved.
  • John explains the adaptive stage which is the first stage yeast enter when you pitch htem into your wort.
  • We talk about fatty acids and sterols and the role they play in yeast growth.
  • John explains the reproduction stage and what’s happening here.
  • He discusses his “sheep” analogy for pitching the right amount of yeast for a particular beer.
  • We explore what happens when you underpitch your yeast (or overpitch)
  • John talks about the role that oxygen plays in yeast development and also several methods for achieving proper aeration.
  • Temperature also plays a key role in yeast growth and fermentation, particularly in the early phases – and we explore that
  • John shares his thoughts on the hibernation stage and storing yeast.
  • We talk about flocculation, the falling out of yeast, and how it can be managed.
  • John shares his closing thoughts on working with yeast.


Thanks to John Palmer for appearing on the show and also to you for listening!

iTunes Announcements: I launched a new video channel for the BeerSmith podcast on iTunes, so subscribe now! At the moment it will only feature the new widescreen episodes (#75 and up). Older episodes are available on my revamped Youtube channel. Also all of my audio episodes are on iTunes now – so grab the older episodes if you missed any.

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{ 2 comments… read them below or add one }

Basil June 29, 2016 at 10:24 pm

> Re: Diacetyl rest, “But never raise above 75F/24C” That’s a pretty standard fermentation temperature for a lot of ales. What do you do if that’s your fermentation temperature?

Jordan July 14, 2016 at 10:25 am

If that’s your fermentation temp, then you almost certainly don’t need to perform a diacetyl rest. A diacetyl rest is most necessary when fermentation happens at a low temperature where the yeast are more likely to go dormant before cleaning up their byproducts (diacetyl being one). If you are fermenting in the 70s, the yeast will have no problem cleaning up at that temperature (unless you have an unusually high-flocculating strain that drops out early, but that’s not necessarily a temperature concern); however, you might have to worry about other off flavors such as fusel alcohols and overproduction of esters, depending on your chosen yeast.

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