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90 Minute Mash

Ok, I searched the forum and read a few things about mash times. On my recent BIAB, I used a 90 minute mash with my mash temps ~152F. I’ve read that opinion is that most of the magic happens in the first 45 minutes.
So what, if any, are the benefits of a 90 minute mash versus a 60 minute mash?

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None that I’m aware of except gives you time to get something else done


I think most of the magic happens in the first 15 min. That said I read that some brewers that keep the mash warm overnight in the oven get great efficiency. Also some cut the mash to 45 min. to save time.

I just use the standard hour, iodine test (that has never failed) and don’t worry about efficiency.

45 minutes is cutting it close. Takes me all of that to go to the grocery store and get back and put the groceries away. I get 80-85% in an hour. Maybe if you get crappy efficiency you could squeeze out a few points. Better off figuring out why and get it done in less time


yup . this.

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I do a 90 minute mash, because it gives me just enough time to get a nice walk in. Doesn’t do a damn thing for the wort though.

IIRC when I was doing iodine tests, 50 minutes where where it stopped turning black.

But for the first 15 minutes thing, I’m sure the function is some sort of exponential decay graph, where most of the change happens quickly, but then there’s a longer, slow tail.

Thanks. I figured I’d try it with this brew. I’d read various forums, online articles, etc. on the subject and it seemed like it really didn’t matter.

@jmck You mean something like this??

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It’s all about fermentability. Efficiency doesn’t improve after about 30 minutes… but much of the sugars you have at that point are not highly fermentable. After 45 minutes, you’re about 85% of the way to the simplest sugars. After 60 minutes, about 90% are simple. After 90 minutes, about 95% simple sugars, which will result in higher attenuation, lower final gravity.

This response partially based on an old Brew Strong podcast from 2015 with John Palmer… as well as ~15 years of my own experience mashing for various times but mostly for 40-45 minutes, because it’s “good enough”.


Me did a experiment 60 over 90 min i dont see any differences

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