When doing a multi-step mash, does the amount of time you take in between steps to raise the temperature make a difference? (Aside from the obvious "taking longer will make your brew day take longer"). I've only done multi-step mashes a few times. The first time I basically had my burner on the whole time and let the mash temp raise from about 120°F to 152°F over about the course of an hour. The second time, I let it rest at each step without any heat and heated between steps as quickly as I could manage to stir without scorching. Raising quickly certainly takes less brew-day time, but I can't say I noticed any difference in the final wort (disclaimer: these two mashes were not the same grist, so it wasn't an experimental comparison, so to speak).

Is there something happening on the enzymatic level that I'm not aware of? Does this make a difference only when using under modified grain?

  • I've wondered a lot about this before. In a lot of mash design software (e.g. BeerSmith) you often see suggested times of about 10 or 15 minutes between steps, which is optimistic without the proper equipment (or an infusion). I think Denny has the right answer, but I'd like to see some more data to support it... – notlesh Apr 6 '14 at 16:05
  • Easy...just try it both ways! And I doubt that those are suggested times as much as they are simply a default. Remember, Beersmith and all other brewing software are tools to help you brew the way you want to brew. They are NOT instructions on how to brew! – Denny Conn Apr 6 '14 at 16:22
  • Indeed, they are defaults -- I'm suggesting it's a safe assumption that they are fairly sane. Incidentally, I'm doing a step mash for an Irish Stout and it took me about 25 minutes to raise from 120F to 150F. I fear I spent too much time in the beta amylase range, but we'll see. – notlesh Apr 6 '14 at 18:22

If you are slow to raise temp between steps, you are in effect spending more time in each enzyme's temp range. This could have an effect on the beer. For instance, if you do a rest at 120ish with a well modified malt (which you shouldn't do anyway!), spending longer in that low temp range can ruin the body and foam of the beer. If you're at a beta rest temp, for instance, a slow rise time will in effect keep you in that beta range longer, which might give yo more activity than you want. While my personal experience is that multi step mashes don't make enough difference to be worth the effort, if you are going to do them you ideally want a quick rise time and a rest at each temp.

  • Ok, that makes perfect sense to me, but that only addresses SLOW rise times. What about FAST rise times? For instance, say I do an acid rest at 95°F and then I heat as fast as I can (ignore the risk of scorching and overshooting for the sake of the argument) up to my saccharification rest at 150°F. Now how will the time spent at each of the other enzyme rest temps along the way affect the final product? Would the times at the passing temp ranges make no difference at all? Would it be better to run the wort of and heat it separately and return it to the mash tun? – user3990 Apr 6 '14 at 22:43
  • Enzymes don't act instantly. Passing through temp ranges quickly (and I guess you'd have to define "quickly") will have minimal effect. – Denny Conn Apr 7 '14 at 15:11
  • Great! Thanks. Do you have a source on how long it takes for enzymes to begin acting? I'm not sure what "quickly" would have to mean either. It would be interesting to know how long the mash would have to sit at a certain temperature before enzymatic action began and determine whether your standard LP burner or electric element would suffice, or if you would have to devise some faster way to apply heat. – user3990 Apr 7 '14 at 16:46
  • In terms of denaturing enzymes, I know that 20 min. is the usually cited amount of time. But I'm not sure how that would relate to conversion times. And I think it kinda depends on exactly what you're looking for. For instance, you may be able to get conversion in 30 min. at 150, but holding that temp longer debranches more starch and makes for a more fermentable wort. I've decided that step mashes really have no benefit to the beer, so I just avoid the whole thing! – Denny Conn Apr 7 '14 at 20:32

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