Ask Mr. Wizard

Warm Fermenting Yeast


Bradley Corrigan - Seattle, Washington asks,

I recently moved to Seattle and do not have air conditioning in my current home so it regularly passes 80 °F (27 °C) inside during the summer. Outside of buying and customizing a freezer to regulate temperature for most beers, are there any types of yeast that would thrive in this environment? The rest of the year fermentation temperature is nearly perfect.


What’s that old adage? When the Pacific Northwest presents you with warm, summer weather get outside and enjoy it before the rain returns. Or is that just the hype intended to ward off the invaders?

Seriously, you state in your question that the temperature is “nearly perfect” for fermentation during all times of the year except for the summer. In my opinion all hobbies deserve a break and it seems to me that your break from brewing should be in the summer. But if you cannot stand to think about such a thing, consider brewing saison, wit, weizen and other styles that have aroma profiles that are enhanced when the fermentation temperature is increased.

Moving beyond the obvious advice, I want to really consider what you have in your climate because this answer is transferrable to other regions that really do have issues. The average August high in Seattle is 76 °F (24 °C) and the average August low is 56 °F (13 °C) according to the website. On the surface of things I am thinking that you can pretty much brew any type of ale that suits your palate, but let’s not focus too much on how perfect your climate is for homebrewing!

One very simple thing you can do is take advantage of this average temperature and use water as a thermal buffer. Simply place your primary fermenter into a large bucket that allows you to fill the larger bucket with water without risking any flow of water into the fermenter. Assuming you placed your fermenter outdoors where the temperature rises and falls during the day, and under the protection of a waterproof box to protect it from radiant heat gain and rain, you could use a very slow water trickle into the outer bucket to create a cooling jacket to remove the heat of fermentation and maintain a relatively constant temperature for your fermenting beer. This method takes advantage of the average August air temperature (which is much cooler than the peak high temperature) and takes advantage of the municipal water temperature.

This line of reasoning should give you some options for brewing in the summer without investing in expensive refrigeration equipment.


Response by Ashton Lewis.