Friday, October 7, 2011

Five Gallons At A Time: Choosing Mash Temperatures

I wish Jamil Zainasheff would stop recommending that brewers mash at high temperatures in his BYO articles. Until I'm a world-renowned brewmaster, though, my opinion is unlikely to count for much. After all, would you take my advice over a guy who's won the freakin' Ninkasi award twice? I wouldn't… at first. But it's important to keep in mind that competition-winning beers are chosen primarily by how well they match a series of written descriptors, not how enjoyable they are or even how much they resemble the commercial beers that inspire the competition style guidelines. Unless you're trying to win medals, your decision-making process should be driven by "which option will make the most pleasing beer?" You'll be constrained by time, money and convenience, but those boundaries aren't very relevant in choosing one single-infusion mash temperature over another. If I were to re-brew all the beers I've ever made, the only ones for which I might choose high mash temperatures (153+ degf) over low ones (149-152 degf) are sour beers.

I've read about commercial breweries conducting short conversion rests at high temperatures and still being able to make dry beers. They may specifically source malt with high levels of beta-amylase. They might employ step mashes that produce a lot of maltose during their temperature ramps. Maybe their mixing methods are particularly efficient. Whatever their reasons, good for them. In my homebrewery, single-infusion mashes at high temperatures do not result in dry beers. They result in high final gravities and syrupy viscosities that make each pint feel like an endurance test. According to some brewers, dextrins - unfermentable (by Saccharomyces cerevisiae, at least) simple starches that are produced in greater concentrations by high-temperature mashes than low-temperature mashes - do not contribute to mouthfeel or body. Maybe dextrins aren't the direct cause, but I'm confident that mash temperatures and mouthfeel are strongly correlated in most homebreweries.

I once had blind faith in the dogma that high mash temperatures were required to combat the inherent wateriness of session beers. The problem? After repeated attempts to get it right, I've still never brewed a good session beer by mashing at a high temperature. Since the time of this happy accident, I've made a number of delicious session beers with low mash temperatures. Not only did they taste great, but they weren't remotely watery. In my opinion, ethanol is an important component of mouthfeel. If I can choose ingredients to layer flavors and build body (or the perception of body) in session beers without high mash temperatures, I don't see any reason to mash high for stronger beers. It's like The Low Budgets say: Aim Low, Get High.


  1. I am just starting homebrewing using extract kits with specialty grains. All the kits call for steeping at 160. Are the temp concerns you are talking about only applicable to all grain or should I be looking at lowering the steeping temperature?

  2. It's only applicable to all-grain brewing. Steep away!

  3. I will say that I have had success making some sessionable beers by mashing high (154ish) and adding a little sugar (less than 5% of extract) to dry them out, thus getting both dextrins and drinkability in the beer. The idea is that this simulates what is done with a number of traditional British session ales. Thoughts on this approach?

  4. I like to use 5-10% Belgian candi syrup in session beers to emulate how English brewers use invert syrups (which I haven't found here, aside from the partially-inverted Lyle's Golden Syrup), but I still mash low. I've never thought to combine high mash temps with simple sugars, and now I'm intrigued. That said, I don't think British brewers typically mash at high temperatures. You should check out By researching actual brewery logbooks and historical textbooks, the author debunks a number of common brewing myths that are often accepted as history. His website was a big reason why my thought process changed from "oops, I mashed this batch too low" to "I should have been mashing low the whole time."


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