New grain mash on top of old grain?

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Steve Broady
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New grain mash on top of old grain?

Post by Steve Broady »

I don't even know what to call this, or how to search for it, but I had an idea and would really appreciate some advice from people that have been doing this for a long time.

Take an AG whiskey mash and ferment it on the grain, then siphon off the clear liquid and distill that. Nothing special so far. Now, instead of squeezing the spend grain, just leave it and pour in the next mash right on top. Keep repeating this until the fermenter gets too full for another batch. At that point, pull out most of the spent grain and either squeeze it or use it to make a sugarhead (I'd probably do the latter). Now the fermenter has some spare room, so repeat the process.

The logic here is to completely avoid having to squeeze the grain, thus speeding up and cleaning up the process considerably. I'm thinking you might also get some UJSSM style generational magic going, and of course not have to pitch new yeast every time. Also, if you use the spent grain to make a sugarhead, there would be a lot more grain in proportion to the sugar compared to using a single batch's worth. That and the residual beer in the grain would presumably make a slightly better, more flavorful sugarhead, and again it would avoid the need to do any squeezing. Unless you squeezed every last drop out of the sugarhead as well, but I'm not sure there's even any point by then.

Is there a name for this that I haven't found yet? Would it hurt anything? Or is it a potentially decent idea?
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Re: New grain mash on top of old grain?

Post by squigglefunk »

some believe in magic, some don't
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Re: New grain mash on top of old grain?

Post by subbrew »

If you are never squeeze and i assume fill to the same level each time your clear liquid volume will decrease as you go. You will also be starting out with higher and higher abv each time as the new to remaining ratio falls. Will that be a problem? Not sure. As long as you are well below the yeast alcohol tolerance level they should keep going. My biggest worry would be the yeast. At some point you have such a huge yeast "pitch" that you no longer get yeast propagation. You just end up with old yeast soldiering on which could introduce some off flavors.

Don't know that it won't work. To me it is one of those things is not one is doing this, I am not a genius that often invents new things, probably a reason it is not being done.
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Re: New grain mash on top of old grain?

Post by zed255 »

I'd think there would be a practical limitation on the number of generations possible. As already noted the volume of new mash vs old mash will diminish, and the residual ABV will climb. You may experience yeast stress, but then again you may be creating a very flavour rich end product.

Guess you can be the pointy end of the stick and report back...
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Re: New grain mash on top of old grain?

Post by Steve Broady »

I should have clarified that my fermentation vessel has extra room. 6 gallon bucket, ~4 gallon mash. So I figure I’ve got room for it to grow a couple generations at least, while keeping each new mash the same ratio of grain to water.
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Re: New grain mash on top of old grain?

Post by Dancing4dan »

Steve Broady wrote: Fri Mar 03, 2023 6:45 am The logic here is to completely avoid having to squeeze the grain, thus speeding up and cleaning up the process considerably.
I HATE the squeeze!

Try this... ferment on grain in a BIAB. Lift the bag after ferment is complete using a pulley system attached to ceiling.(buy a pulley system from Canadian Tire, Hunting section) Let gravity drain as much as possible. Then fasten a zip tie around the top to the BIAG and slide it down to the grain ball in the bag. (I like the zip ties with the little release so they can be used over and over.) Do some feeble weak ass grain squeezing. I hate the squeeze! Re-adjust the zip tie so the grain ball is nice bunched up and tight. Tie a length of cord (paracord works great) around the grain ball. Use a simple knot and use it to squeeze a bit. Then tie it off in a square knot. Insert a chopstick or something similar between the bag and cord and start twisting the cord with the stick, like a tourniquet. This squeezes the grain! Use multiple lengths of cord on grain ball and a few chopsticks to do the twist. Let it all hang over your wash as it drips and have a nice sip of your last whisky while you relax and watch.

Now you can cold crash, rack off and distill. AND you can put the BIAB back into the fermenter with the grain. Add another batch of grain or do a sugar head!

Easy squeezy! No mess. Ver little work.

I hate the squeeze! :thumbup:

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Re: New grain mash on top of old grain?

Post by higgins »

If you were to save a specific amount of spent mash each time you could have a perpetual fermentation going on.

Based on 5 gallon batches, ferment on grain, gravity drain, discard all except 1 gallon of mash.
pitch new mash onto saved gallon, ferment
repeat

Should be able to go on forever, no?

As a 30 yr AG brewer, I have used yeast for up to 7 generations for making beer. Beer contains many proteins, both fermentable and non-fermentable, which can lead to spoilage, so sanitation is very important in brewing. Accordingly, yeast re-use must be done with a higher level of sanitation than is necessary in this hobby. Even in the most sanitary conditions I could achieve the yeast would change over that time, so every few years I'd discard that yeast and start over with a new smackpack. I kept 5 or 6 different strains going like this.

If you can keep it fairly sanitary (not to the degree necessary for beer) it should go on and on without buildup of undesired elements. Of course, any contaminations (such as lacto) will carry over. It will unavoidably change over time, so maybe go X number of generations and start over.

BUT: Even expensive yeast is cheap compared to the ingredients for the product. When I make a whiskey I'll shoot for around 40 gallons of 8% wash to net about 1.5 - 2 gallons of 125p hearts. For bourbon that's about $50-80 in ingredients; for single malt around $150-200. I use FermSolutions FS917 yeast for bourbon (about $16 per lb, $1.50 per batch), and Fermentis US05 for single malt (8 pk for $25, 2 pks per batch). So the yeast cost is a very small portion of the overall cost.
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Re: New grain mash on top of old grain?

Post by Steve Broady »

zed255 wrote: Fri Mar 03, 2023 1:49 pm Guess you can be the pointy end of the stick and report back...
I’m thinking I’ll do that, Zed. It’s worth a try, at least. Anything I can do to simplify and speed up the process would be welcome, as I simply don’t have all day to devote to this, let alone multiple days. I typically have 48 hours off in a week, and in that time I have to be a father, husband, homeowner, cook, repairman, and hopefully find a few hours left for myself and get enough sleep. So 12-14 simply isn’t in the cards, and probably won’t be for years.
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Re: New grain mash on top of old grain?

Post by Steve Broady »

higgins wrote: Fri Mar 03, 2023 6:22 pm Should be able to go on forever, no?

If you can keep it fairly sanitary (not to the degree necessary for beer) it should go on and on without buildup of undesired elements. Of course, any contaminations (such as lacto) will carry over. It will unavoidably change over time, so maybe go X number of generations and start over.
Well, I know that some people have many years and countless generations of UJSSM in their sheds, so I don’t see why I can’t do the same with whiskey. It seems like I’d just be replacing the sugar with sugars from grain, right? I made 6-7 generations of UJSSM, and I definitely noticed a flavor change around gen 5. If whatever “magic” (for lack of a better, more scientific explanation) happened there can happen in my whiskey, I’d be thrilled.
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Re: New grain mash on top of old grain?

Post by EricTheRed »

higgins wrote: Fri Mar 03, 2023 6:22 pm When I make a whiskey I'll shoot for around 40 gallons of 8% wash to net about 1.5 - 2 gallons of 125p hearts.
How tight are your cuts?
On 100 litres 10% wash i get 10ish litres at 63% abv.
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Re: New grain mash on top of old grain?

Post by NZChris »

As long as you discard about the same amount of grain as you add to each generation, you won't run out of space in your fermenter regardless of what product you are making.

As long as you discard about the same amount of heads and tails congeners with each generation, you won't start reducing the volume of your heart cut selection.

Your own notes of what you do are of more value than anything we can add because we don't know how you do your cuts, or what your flavor preferences are.
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Re: New grain mash on top of old grain?

Post by higgins »

EricTheRed wrote: Fri Mar 03, 2023 7:34 pm
higgins wrote: Fri Mar 03, 2023 6:22 pm When I make a whiskey I'll shoot for around 40 gallons of 8% wash to net about 1.5 - 2 gallons of 125p hearts.
How tight are your cuts?
On 100 litres 10% wash i get 10ish litres at 63% abv.
I use a pot still.

40 gal of 8% = 3.2 proof gallons. 2 gal keep @ 62.5% = 1.25 proof gallons, so I keep around 39-40% of the alcohol.
100 L of 10% = 2.64 proof gallons. 10 L keep @ 63% = 1.65 proof gallons, so you keep around 62% of your alcohol.

My cuts are rather narrow, usually around 40% of what I collect (I strip to < 5% ABV off the spout, spirit run to 15% off the spout). I'll adjust my jar size so I'll collect 24 jars, of which I'll usually keep 8-10 jars out of the middle. I run at around 1.75 LPH, so maybe I'm smearing a bit more than others. But soon I'll be running whiskey using my new 4" 3 plate flute, so should be able to increase the hearts cut.
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Re: New grain mash on top of old grain?

Post by jonnys_spirit »

I do similar after an AG - remove about 1/2 spent grain, mash in “a good bit more”, top up with molasses and/or sugar/panela. I call that my rat-bastard-rumski and can continue practically forever.

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Re: New grain mash on top of old grain?

Post by Deplorable »

I just don't get why people are so hung up over "the squeeze". It's not that hard, and it doesn't have to be messy. It takes me less than 2 hours to empty my 30 gallon fermenter of a finished ferment, squeeze 50 pounds of grain, wash everything, and put it all away. I'm not in any hurry to get it done either. I could probably shave some time off my process if I wasn't trying to get the grain as dry as possible with the mop wringer.
Its arguably the quickest part of the process compared to mashing, stripping and spirit runs.

I get sugarheads, but for an AG product even making multiple successive ferments of it, you'll be further ahead in the long run if you empty the fermenter and start a new mash from the ground up.
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Re: New grain mash on top of old grain?

Post by EricTheRed »

higgins wrote: Sat Mar 04, 2023 7:30 am
EricTheRed wrote: Fri Mar 03, 2023 7:34 pm
higgins wrote: Fri Mar 03, 2023 6:22 pm When I make a whiskey I'll shoot for around 40 gallons of 8% wash to net about 1.5 - 2 gallons of 125p hearts.
How tight are your cuts?
On 100 litres 10% wash i get 10ish litres at 63% abv.
I use a pot still.

40 gal of 8% = 3.2 proof gallons. 2 gal keep @ 62.5% = 1.25 proof gallons, so I keep around 39-40% of the alcohol.
100 L of 10% = 2.64 proof gallons. 10 L keep @ 63% = 1.65 proof gallons, so you keep around 62% of your alcohol.

My cuts are rather narrow, usually around 40% of what I collect (I strip to < 5% ABV off the spout, spirit run to 15% off the spout). I'll adjust my jar size so I'll collect 24 jars, of which I'll usually keep 8-10 jars out of the middle. I run at around 1.75 LPH, so maybe I'm smearing a bit more than others. But soon I'll be running whiskey using my new 4" 3 plate flute, so should be able to increase the hearts cut.
😁 nice
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Re: New grain mash on top of old grain?

Post by Steve Broady »

For all of those who said this was a bad idea…

You were right.

I tried it, because I figured it was worth trying at least once. Maybe if I had a bigger fermenter, it would have worked better. But as it is, I managed to overflow the fermenter.
And then when I decided to squeeze it after all, because there’s a LOT of liquid trapped in there, I had to deal with two batches worth. And then I out it all back in for the sugar head, and overfilled toe fermenter again. At least this time I knew to take some out and let it go separately.

Oh well. Live and learn. I admit to being an idiot.
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Re: New grain mash on top of old grain?

Post by bilgriss »

Learning is good.
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Re: New grain mash on top of old grain?

Post by Bee »

I think it's more practical to do the all grain, then throw sugar into the fermenter and top off with water for a sugar head.
Drink the sugar head white and use the AG for long term aging.
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