Double mashing (2 sets of grain)

Hi all,
Just sitting here at work thinking. I read somewhere about double mashing with two sets of grain to achieve higher gravity wort. That is to mash with one set of grains and then bring that wort up to temp, replace the grains with a new set of grains and mash with the wort (like if you are limited on mash tun space). What is this called? Does Beersmith have a setting/calculation for this? Or do you just split the grain bill in half? Was thinking of doing this with a barley wine since we currently have only a small cooler (10gal). Also was thinking you could mash to get say 1.25OG to make appx. 24% estimated, then double it with water in the large fermentor to make 12%? Is my theory sound or should I stop thinking? We have a 20 gallon fermentor that's being neglected.

It's called a reiterative mash. I'm skeptical in its benefit because it still takes 60-90 extra minutes and you might as well just mash once, fully sparge it, and spend that extra hour boiling down. Of course, if you're trying to make 10 gallons of barleywine, two mashes would be required. What is your kettle capacity?

We have a 65 gallon stainless tank we can boil in (only used it with test water so far), the most I would be boiling in it at this point is appx. 20 gallons because our fermentor will hold appx. 18 gallons. Our limiter right now is the tun, hence the question. I see no other way to increase gravity short of boiling for 5 hrs, then you'd have to do two batches anyway, for volume. I'd rather do 2-3 hrs mash time than 10 hrs boil time.

Bobby_M said:

What is your kettle capacity?

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That is exactly the reason why I'm not at all skeptical of this process. I will be trying this soon when I brew up my first AG RIS. I only have a 7.5 gallon kettle, just big enough to stand over and watch the whole time you're doing a full boil so it doesn't boil over....sux. It is a great option for newbs and cheapskates like me.

Mosher talks about this in his book, Radical Brewing. He calls it double double. I think he gives some formulas and some other high gravity techniques. Look up the formula for no sparge brewing for the formulas for gavity.

Do the no sparge for the high gavity then do a pari-gyle with the semi spent grain. You could do it like a batch sparge for times sake. A few buckets should do nicely if you don't have the extra fermenters on hand.

This way you can have two batches for the price of one + a few buckets.

SnickASaurusRex said:

Mosher talks about this in his book, Radical Brewing. He calls it double double. I think he gives some formulas and some other high gravity techniques. Look up the formula for no sparge brewing for the formulas for gavity.

Do the no sparge for the high gavity then do a pari-gyle with the semi spent grain. You could do it like a batch sparge for times sake. A few buckets should do nicely if you don't have the extra fermenters on hand.

This way you can have two batches for the price of one + a few buckets.

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Have done this, it makes a good small beer as second batch. I think that's where I read it (Radical Brewing) I'll have to peruse it again.

I wouldn't do a reiterated mash unless you have a good plan for a partigyle, you'd waste too much grain to make it worthwhile.

I posted about a partigyle I did here which used a mini-mash, which totally rocked, the smoked porter is on tap now and it's one of the best homebrews I've ever made.

I did just this last Fall! I normally don't brew big beers, but I was trying to use up that last of the old grain before starting in on the new. I mashed in, and then drained, sparge, etc. as normal but then cleaned out the tun, and put the wort back in, brought it up to mash in temps and added the rest of the grain and proceed as if normal. I can't remember how many lbs of grain I used (17 - 20 lb). I did a normal 90 min. boil (pilsner malt) and had a OG of 1.10 into the fermenter. It took a few tricks, but the final OG was 1.008 or 13% ABV. It's in the keg and will sit there until at least fall.

I agree that doing any batch where only the mash runnings are used for a specific beer is extremely wasteful if you don't have any small beer plans for the sparge. The small beer off my English Barleywine turned into one of the best ESB's I've made.

A 28lb maris otter grain bill turned into 5 gallons of 1.15 wort and 5 gallons of 1.055 wort.

pjj2ba said:

I did just this last Fall! I normally don't brew big beers, but I was trying to use up that last of the old grain before starting in on the new. I mashed in, and then drained, sparge, etc. as normal but then cleaned out the tun, and put the wort back in, brought it up to mash in temps and added the rest of the grain and proceed as if normal. I can't remember how many lbs of grain I used (17 - 20 lb). I did a normal 90 min. boil (pilsner malt) and had a OG of 1.10 into the fermenter. It took a few tricks, but the final OG was 1.008 or 13% ABV. It's in the keg and will sit there until at least fall.

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This is more like what I am talking about, what's wrong with doing this?:rockin: