high gravity, double mash technique

I think I am going to try a double mash on my next brew. I want to make a HUGE RIS and so I think I will use the double mash technique where you conduct one mash, collect the wort, reheat it and use it to mash in the second mash. I suppose you could do it a third time if you wanted.

Any brewers out there have experience with this? I think it is straight forward enough.

I haven't done it, but I think there was an article on it in the last BYO.

Professor Frink said:

I haven't done it, but I think there was an article on it in the last BYO.

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I read an article recently about it, but I have not gone hunting yet!

I say go for it, I'm curious about how it comes out.

I did it once. Dimininshing returns. My efficiency on the second mash was way down, like 40% down, the second time around.

But I had some gravity points in my water by golly.

Wasteful of men and barley FTUW!!

I may be missing the point, but aren't any sugars left over after the original mash going to be a lot less soluable in the wort than they would be in water? Or is the point to collect extra gavity points without risking tannin extraction?

I wonder if it would help to save the sparges from the first mash seperately (if batch sparging) (don't mix them) and then use the second sparge, the thinnest wort, for the mash-in on the second mash. Then use the first runnings, then the second sparge, and then sparge to get the boil volume. This might work a bit better, since your mash-in wouldn't already be saturated with sugars.

I didn't know about this technique, I may try this some day for a dubbel or trippel.

The idea of a reiterated mash is to raise the gravity of the wort without raising the volume of the wort. It is a very low efficiency procedure from a mashing perspective, but it saves you a bunch of boiloff. If you use your second runnings for another beer (or, maybe, a couple more beers), it actually can be quite efficient.

I haven't done it, myself, Brewpastor, but I've talked to some folks that have. It is just as straight forward as you described. Here is the HBT thread on it a little while back.


TL

I applaude your willingness to try it.

I would just ask that you either do a (hardly) part-gyle right after it (the grains would still have lots of goodness) or let me come and pick up the *ahem* spent grains!

Sorry! I just hate grain abuse!

theres a podcast on reiterated mashing on basic brewing radio...I think it was with chris colby of byo..that should get you started

I did listen to that podcast and while it sounds interesting, it's also almost twice the brewday. If the mashtun is big enough, you might as well partigyle and use the big first runnings.

The way I look at it is, if you have to do two mashes, you might as well do two separate mashes and only use first runnings from both. That is, two partigyle mashes where you combine both first runnings for the big beer and both sparge runnings for the small beer. Sparging with high gravity wort is intuitively counterproductive.

It just seems.... odd. Using sugary wort-water to rinse more sugars out?

I'm with Bobby; I'd get a friend over and borrow their mash tun. Actually, that could be a fun brew day; both people do the same mash, collect the first runnings from both for the big beer, the second runnings for the second beer. Each person then does their own boil separately. Split the beer after it's fermented. Ten-gallon batches, each person gets a cornie of each beer.

The idea is to increase your wort gravity without increasing your wort volume. It is terribly inefficient, but it another way of doing things.


TL

This method will get you better/higher gravity (or so they say) then first runnings.

i haven't been on the up and up with my brewing lately but i'm getting back into it more now that i'm able to brew again. is it possible to mash, sparge(or just drain without sparging) then do a second mash with the same grains and new water?? i'm i totally missing the boat on this idea or does this make sense? will the enzymes try and convert any leftover starches? is there any more starch left after the first mash???

i'm intrigued, more info, need input!!! lol

Yep, you can do that. Search around for "partigyle" and other weird spellings.


TL

the_bird said:

It just seems.... odd. Using sugary wort-water to rinse more sugars out?

I'm with Bobby; I'd get a friend over and borrow their mash tun. Actually, that could be a fun brew day; both people do the same mash, collect the first runnings from both for the big beer, the second runnings for the second beer. Each person then does their own boil separately. Split the beer after it's fermented. Ten-gallon batches, each person gets a cornie of each beer.

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Bird that sounds like fun. When can I come over?

this morning I brewed a 13 litre SMASH beer with OG 15.0 BRIX - from experience I know the FG will be 9.5 BRIX - I want more abv than that so next time I will add 8 litres of water to the wort, heat to 75 deg C and add another 8 lb of pale malt, mash for an hour at 69/70 deg C and collect the wort - would hope for OG 20.0 BRIX.............

http://awesomebrewers.com/bm/Brew-Jobs/parti-gyle-like-its-1999.shtml
So they call it a parti gyle but it is also a reiterated mash...
Brewers be crazy sometimes...

SirHC_ said:

http://awesomebrewers.com/bm/Brew-Jobs/parti-gyle-like-its-1999.shtml
So they call it a parti gyle but it is also a reiterated mash...
Brewers be crazy sometimes...

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Not the same. The way I understand it is in reiterated mashing you use the runnings from the first mash as the strike water for a second mash. All of it goes into one beer. When you partigyle you are making two different beers. One using just the first runnings and the other using just the second runnings. And even that is not true partigyling.

There was also a good episode on this on Brew Strong, where J. Blichmann presented some numbers from his trials.

kevin58 said:

Not the same. The way I understand it is in reiterated mashing you use the runnings from the first mash as the strike water for a second mash. All of it goes into one beer. When you partigyle you are making two different beers. One using just the first runnings and the other using just the second runnings. And even that is not true partigyling.

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Did you read the post? As I read it, the brewers mashed in one pot and used those runnings to mash the next pot of fresh grains. A reiterated mash, yes? They used their reiterated mash runnings for a quad, with the additional sugars so common in Belgian beers.
They then did the modern pseudo- partigyle and did a second reiterated mash for a dubbel.
I've done both a proper PG and the more common method amongst home Brewers, imho, of simply fermenting separate runnings separately.
The guys above kindof did a "mashup" of two techniques, pun totally intended. Their way addresses some of the concerns posted above about the efficiency issues in a reiterated mash...make more beer!

Sorry to resurrect an old thread, but I tried a similar thing for my last brew. Not a reiterated mash but using the 1st runnings as sparge water.

I've got a frankenstein BIAB/mash tun set up where I mash in a bag inside a small cooler. I use a 4 gallon kettle for 3 gallon batches (small space, limited storage). Because of the small kettle, getting enough water to mash a full grain bill & sparge without overfilling the kettle can be tricky.

ANYWAY, this last time around I decided to mash with the full amount of water needed, then heat that wort up to 170F before using it as sparge water. Target OG for this beer was 1.055.

Boiled down to just under expected volume, cooled to 60F and checked OG. It was 1.081!! Measured twice, checked hydrometer. Seems like a legit reading. Any thoughts? Easy way to boost efficiency with small kettle? Easy way to accidentally brew a way-too-strong ESB?

lcram said:

Sorry to resurrect an old thread, but I tried a similar thing for my last brew. Not a reiterated mash but using the 1st runnings as sparge water.

I've got a frankenstein BIAB/mash tun set up where I mash in a bag inside a small cooler. I use a 4 gallon kettle for 3 gallon batches (small space, limited storage). Because of the small kettle, getting enough water to mash a full grain bill & sparge without overfilling the kettle can be tricky.

ANYWAY, this last time around I decided to mash with the full amount of water needed, then heat that wort up to 170F before using it as sparge water. Target OG for this beer was 1.055.

Boiled down to just under expected volume, cooled to 60F and checked OG. It was 1.081!! Measured twice, checked hydrometer. Seems like a legit reading. Any thoughts? Easy way to boost efficiency with small kettle? Easy way to accidentally brew a way-too-strong ESB?

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Sorry to burst your bubble, but all you did was a full volume, no-sparge, with a full volume vorlauf. Vorlaufing with the full wort volume will not give you an increase in efficiency.

Mash efficiency is comprised of two factors: conversion efficiency and lauter efficiency. Conversion efficiency is the percentage of starch in the grain that you actually convert to soluble sugars, and lauter efficiency is the percentage of sugars that were created by conversion that actually end up in your BK. Lauter efficiency is always less than 100%, because some of the wort is retained in the spent grain.

Sparging is using fresh water to rinse some (usually most) of the residual sugar out of the spent grain by diluting the wort that was originally retained. The grain ends up retaining the same amount of liquid, but now the retained liquid is lower SG than the original wort, so less of the total sugar is left in the spent grain. This increases lauter efficiency, but has no effect on conversion efficiency.

You may have gotten an increase in conversion efficiency from doing a mash-out (heating the mash to 170 before draining.) This effectively extends the mash time to allow more conversion, and the conversion proceeds faster at higher temperatures, until all the amylase enzymes are denatured.

You can increase mash efficiency either by increasing conversion efficiency, increasing lauter efficiency, or increasing both.

Brew on

lcram said:

Boiled down to just under expected volume, cooled to 60F and checked OG. It was 1.081!! Measured twice, checked hydrometer. Seems like a legit reading. Any thoughts? Easy way to boost efficiency with small kettle? Easy way to accidentally brew a way-too-strong ESB?

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As @doug293cz said, you did a no sparge, with a really big vorlauf. And your mashout could have improved conversion efficiency a little.

But a legitimately expected post boil OG of 1.055 coming in at 1.080? I'm not buying it. There's either a measurement error, or the expected OG of 1.055 was based on a really low expected mash efficiency.

Fortunately, this is easy enough to figure out. What was your grain bill and your exact post boil volume?