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Slower/cooler is Better for Ferment?

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D-brewmeister

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Just curious if there might be some cases where a slower fermentation might be preferable. I do clearly understand the value of having as little lag time as possible between brew and ferment, as well as a vigorous start to fermentation -- all to limit the impact of possible contaminations. But I remember reading that many breweries brew at colder temps than most of us homebrewers, even for ales. And I assume a colder ferment equals a slower ferment (as I understand from looking at expected times for Lagering). What are the specific benefits to cooling down fermentation (something about esters?) and lengthening the process? I currently have an Alt in primary, and after an initial period of fermentation in the mid 70's, I have succeded in cooling it down to about 63 degrees via evaporative cooling (a wet towl and a fan), and plan on puting my secondary in the basement, in the mid 50's. Any input on how this sort of cooling might affect other ale recipes, like pale ales or IPAs (my next planned batch).
 

Janx

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You're absolutely right...striving to have as little time between chilling and the beginning of fermentation does not equal fast fermentation times. The former is definitely a good thing in all cases. The latter depends on your preference.

Fermenting ales in cooler temperature ranges will definitely slow things down. Assuming a "normal" gravity ale (like below 1.060), the fermentation should be fine but slower. You will definitely get less esters, fruity flavors and yeast characteristics than you would from a hotter ferment. You'll get fewer fusel alcohols. In general, you'll get a cleaner flavor.

Now, in some cases a hotter ferment is desirable. Maybe you want a more estery beer. Many British ales have a distinct yeasty/estery character. Some Belgians get most of their flavor from esters.

Also, when brewing higher gravity ales, it may be preferrable to ferment at higher temperatures. To some extent, with brews over 1.060, you need to "charge" the ferment. In other words, get the yeast really raging so they can finish the beer. Picture the coyote running well past the edge of the cliff before actually falling down. In high gravity beers, the yeast will kill itself by making the environment so alcoholic. So a quicker ferment is better so that it actually ferments dry. Of course, yeast strain has a huge impact on whether a high gravity beer will finish or not.

Anyway, there's some stuff to think about. We often leave our secondary ales in the shed outside so they have a cooler secondary. Especially for APA or American IPA. Cheers! :D
 
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