Double-mash: Would this work?

Discussion in 'General Brewing Discussions' started by Donoroto, Jan 25, 2021.

  1. Donoroto

    Donoroto Well-Known Member

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    Just idly thinking out loud here.

    Say I wanted to create a higher-gravity wort. If I mashed a full grain load, sparged, then mashed again with another full grain load using the just-mashed wort, is it accurate to expect the gravity to increase substantially? I can't imagine it would double, but 150-180% of the first mashing seems plausible.

    Or to put it a different way: My system can handle 14 pounds of grain, but that's the limit. What if I were to mash two 10-pound batches, am I wrong to expect a higher gravity than just a single 14-pound mash?

    And no, I know I can use DME, LME or Candi syrup to the same effect. This is more a hypothetical than 'I'm-a gonns do this'. (But I might...)
     
  2. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    I have heard of this technique and I know it works, but I don't know what the extraction rate would be. It's a good way to increase gravity without a billion hour boil. I hate those.
     
  3. BarbarianBrewer

    BarbarianBrewer Well-Known Member

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    I know I've read about this....just can't remember where. I'll post back here if I can get those brain cells back online. From what I do remember, the results were in the ballpark of what you would be expecting; a significant boost in gravity but no where near a doubling.
     
  4. Craigerrr

    Craigerrr Well-Known Member

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    Genus brewing has a video on doing a really big beer in a robobrew. Not sure if that would help.
     
  5. J A

    J A Well-Known Member

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    It's called a reiterated mash. Yes it'll work quite well but it's pretty inefficient.
    Just google it and you'll find a lot of info and articles that document the process and the results.
    I've thought that instead of using the entire runnings from the first mash, you could hold back first runnings (highest gravity) and use the result of a good sparge to start the second mash. The first runnings from the second mash would be substantially higher than the first mash. Using first runnings from both mashes at that point should give quite high gravity wort.
     
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  6. Donoroto

    Donoroto Well-Known Member

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    First, thanks for the name. That always helps, to be able to name a thing.

    Second, I like the idea of the second mashing starting with the sparge water. One thought is to mash with a smaller grain bill, and so using less water is OK, meaning at the end getting 7 gallons pre-boil is reasonably do-able (as opposed to 9 gallons!)

    On my list to try this year some time. Next is a refill of the house hefeweitzen, on deck is the Herms Amber Ale.
     
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  7. Nosybear

    Nosybear Well-Known Member

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    If a thing has a name, you know you weren't the first to think of it and that can be comforting in itself.
     
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  8. Mark Farrall

    Mark Farrall Well-Known Member

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    I haven't done one yet, but I'm planning on doing this for my next imperial batch. I'm not really looking for great gravity increases in the second mash, just avoiding the challenges of using BIAB on grain volumes 2-3 times larger than my normal process.

    I'm normally doing 12-15 litre batches, so I'm easily able to hold and squeeze the bag for them. But with the 10% beers the bag is just too heavy and I'm getting a bunch of losses just removing the bag. I'll probably go with a 60/40 split of the grains for the two mashes and will probably keep most of the roasted grains for the second mash.
     
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  9. Head First

    Head First Well-Known Member

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    Appling this type of mash to the all in 1 systems could be a very good thing. It seems I am always trying to mash to thick with all the extra space under the malt pipe. If grain was split at the right percent it could be much easier for thinner mash and as pointed out could do bigger beers much simpler without riding the kettle rim. Hmm:rolleyes: Good food for thought.
     
  10. Steelyace

    Steelyace Member

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    I have done this on a big beer, but don't remember all the stats of the beer. It does work....but the second mash you do is far less efficient than the first, from what I've experienced. It is lower because you already have a wort that is quite saturated at that point in time. I personally think that a better option is a complete double mash and a longer boil, in my opinion.

    If I was to do it again, and probably will sometime, I would plan on @60-65% efficiency for the first mash and for the second mash I would plan on @50%. I would also recommend a longer mash time for the second mash.
     
  11. Donoroto

    Donoroto Well-Known Member

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    This is exactly where I was coming from.

    Anyone have any thoughts of the downside(s) of a longer boil?
     
  12. Megary

    Megary Well-Known Member

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    ***Pause***

    I've got nothing to add other than I think this thread is fascinating. I've spent far too much time now searching the web for Double mashing, reiterated mashing, partigyle etc. I have plans to make a Barleywine in late May/early June and thought - given my BIAB set up - that I would split the grains into 2 separate pots (since the large grain bill won't fit into one), mash each as I would normally, then mix both mashes and just boil (a lot) longer. My thinking is that a Barleywine might actually benefit from the coloring of a longer boil/maillard reaction/caramelization. No idea. Just trying to convince myself. Great thread.

    ***Resume***
     
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  13. Hawkbox

    Hawkbox Well-Known Member

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    It'll change your math a bit for hops but otherwise I see no downsides. I do it occasionally when I don't boil off as fast as I expect.
     
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  14. Donoroto

    Donoroto Well-Known Member

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    Of course, optimize your boil by running a small house fan to blow away the steam. You can bump up the evaporation rate 15-20%.

    Ah, I hadn't thought about darkening from Maillard reactions, but then again color isn't terribly important to me.
    So longer boil it is! But not for a while, I have other priorities at the moment.
     
  15. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    The Maillatd reaction can be diminished by starting with a low boil pH of 5.1-5.2. The higher the pH the darker the beer gets from the boil. Another thing that keeps the beer from getting too dark is campden tablet in the mash. 550 mg for a 5 gallon batch. It works really well, it’s a technique used by the LODO brewers to avoid hot side aeration in the mash. The metabisulfite is driven off in the boil.
     
  16. Hawkbox

    Hawkbox Well-Known Member

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    I have serious doubts about claims of Maillard reactions, wort doesn't get anywhere near hot enough for that in our time frames.
     
  17. Head First

    Head First Well-Known Member

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    You don't make a 14% abv all grain beer without some boiling. A brewery in Missoula MT, Kettlehouse brews a scottish ale that the recipe from the brewmaster ccalls for a 2hr boil. It is a yummy beer. It's over 6% abv so he is playing with flavors in doing it.
     
  18. Nosybear

    Nosybear Well-Known Member

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    It gets hot enough for Maillard reactions which can occur at room temperature. Caramelization may be what you were thinking of.
     
  19. Hawkbox

    Hawkbox Well-Known Member

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    Yes but not in an hour. I'm talking about "The reaction is a form of non-enzymatic browning which typically proceeds rapidly from around 140 to 165 °C (280 to 330 °F)."
    I would attribute any colour change in an hour to concentration of wort long before I would assume a Maillard reaction caused it.
     
  20. Nosybear

    Nosybear Well-Known Member

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    All I know there is what I read. At those temperatures you're talking about caramelization. If I do homemade caramel, that's what causes the change of color and flavor. Maillard reactions are browning reactions that take place at much lower temperatures, even room temperature.
     

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