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Maximizing grain mash abv

Paul Tomaszewski

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Folks, recently fully licensed and producing and having issues to work through (and I know we will continue to have them for quite a while being that we had to start up the "iron man" way without a whole lot of funding or welding experience). In the immediate, our biggest issue (imho) is getting our abv up for our grain mashes so our runs on the still are a bit better. Our main products are all-grain (corn whiskey) and are hovering around a low 5% abv prior to distilling. I'd like to try to get that up, even if just a little, but not sure if it's possible until we upgrade our equipment. Right now we're using a 50 gal. steel pot for mashing using a propane burner, so we can't keep the burner going when we put the grain in. We get the water/sour mash up to boiling, cut heat, add cracked corn, stir every 15 mins, allow it to cook down for a good, solid 90 mins. The lowest the temp will drop is usually 185 F. We then drop the temp (using ice) down to 155 for adding malt and then allow that to work its magic for a good 2 hours (stirring every 30 mins). I've tried adding additional enzymes, doesn't seem to make a lick of difference. When we move the mash to the fermenter, we have to separate/strain the grain by hand because we can't put the solids in the still and I'm not comfortable with risking moving the solids with our diaphragm pump based on the manufacturer's recommendations (plus it isn't fun to get that grain out of the fermenter after we would pump out the liquids). I know that we're doing it pretty rudimentary, but that's what we've got to work with until we can build up a bit. And to answer some questions up front, no we can't soak the corn prior to (it's cracked and we use the heck out of the cooker being that it takes 3 cooks to fill a fermenter, that's also why we have to move the mash once it's done enough so we can begin another cook). Our products are turning out great, we just can't produce a whole lot going on like this and we'd like to start stocking as many shelves as possible. All of that being said, maybe someone can recommend a cheap 150-250 gal. cooker that will alleviate most or all of this. It is in the cards to upgrade most/all of our equipment as soon as we can, so I realize that. Any feedback, suggestions are greatly appreciated, thanks guys.

Paul & MB

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Without knowing how much corn/water you're using, it's impossible to be sure, but I think I see some things you can do to improve the situation.

Easy fix: switch to pre-gelatinized corn flakes.

(1) you're probably not getting full gelatinization,

(2) you're throwing away sugars before the fermenter,

(3) you're throwing away ethanol before the still.

Biggest concern is cracked corn. Get a hammer mill and set it for 1mm maximum size. This will improve gelatinization and extraction later. With this smaller size, your pump may be happy, and you may feel more comfortable putting the solids into the fermenter and later into the still (presuming you're using steam, not direct fire).

Even this may not be sufficient to get full gelatinization - the better cooker will help with that. Gotta break-down those starch granules before the enzymes will do anything.

Have you done the math on how much starch you're buying when you get the corn, how much sugar that should yield, and therefore how much ethanol you should get?

$0.02 clinks into the kitty

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Ok... the postor above went through the possiblity that you have lack of sufficient starting gravity due to process issues quite well. But, there could be other things at play that are compromising your results.

What was the starting gravity of the wash?

Here are a couple of other common sources that can cause what you are experiencing:

If the SG was on target and you are only getting to 5%, another common reason for this is too high of a fermentation temperature. You also might be underpitching the yeast as well. Whiskey ferments should be in the same range as ale fermentations... ie... under 78 Deg. F. Yeast activity creates heat, therefore if you are pitching anywhere above this temperature you can compromise the fermentation by killing off some of the yeast. Also, if you are pitching into too high of a starting gravity, the osmotic pressure might be too high and that also compromises yeast performance.

Post back with the starting gravity and that will allow me to better theorize where your difficulties are coming from.

Eric Watson

Master Distiller

Cayman Islands Distilleries, LTD

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Will's right, unless you know how many lbs of corn and how much water you're adding, this is all a bit of a moot point. You also need some specs from the Corn and Malt to calculate an expected yield.

That said, you really need to mechanically tear up the walls and membranes that holds the pockets of starch using a hammer mill, and then boil the corn if (if) you're looking for maximum yield. The matrix of starch is protected by materials that regular ol' amylases won't break down, so that's why liquid enzymes are of little use. It's a bit like taking un-milled brewer's malt, adding water and artificial enzymes, and expecting to turn the malt into liquid maltose....your yield would be close to zero, as the malt starch is protected from enzyme attack by the barley's husk. IMHO, you're biggest problem is your milling. Perhaps there's a local mill that can help you. Maybe even a bakery will have a hammer mill you can use once a week. Just a thought.

If you can't get access to new equipment (a hammer mill and a corn cooker...or maybe add an impeller to the 50 gal cooker you have), I'd consider switching to flaked corn, even if it's just a portion of your mash (if you're worried about keeping the properties of your germ).

Oh, and IMHO, your saccharification temp is too high. I'd also take a careful look at how much oxygen you're adding before pitching yeast...not adding enough is a real easy way to stop your fermentation short, especially in a high gravity mash/wort.

Just an opinion. There's a 1,000 different ways to get there.

Good to see a fellow Siebel grad, madmacaw. Graduated in 1996.

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I wonder about temperature, but 155f (63c) is in the zone for alpha, but I've seen temperatures as high as 95c (203f) quoted in current literature:

Carr et al

While the traditional method is to steam the corn to nearly boiling for gelatinization (and i've seen other references to steaming for extended periods) then drop the temperature to 40c, add malt, raise to 55c for beta, then to 65c for alpha and sterilization. I don't see how Paul's equipment can be used for this procedure...and it's clear that he's getting some saccharification...so alpha is working.


With cracked corn, the granules are not available to be gelatinized. Add to that low gelatinization temps and filtering the wash before fermentation, and I see a bad story for the bank account.

...but I repeat myself.


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I'm using 2 lbs. grain to each gal. of water, 80% corn, 20% malt. In the case of corn, I'm using food-grade white corn, it does give the spirit a sweeter flavor, so can't use flaked all the way. I could supplement some flaked into the mash bill, but I wouldn't want to use too much. Other than buying a hammer mill, the best I can do is crack the corn again (obviously that will only go so far). Don't suppose any of you have any recommendations for a cheap hammer mill? Being on the poor man's plan, the still is also part of the issue, can't put the grain in it. Therefore, we have to siphon out the grain prior to going into the fermenters (and it ain't fun). One day I'll look back on all of this and laugh... ha ha.

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Well, without making some modifications, or changing your ingredients, I don't know what to tell you. I wish that I could be more helpful. You can't get the yield you're looking for without a hammer mill. And most especially if you're trying to "strain" out the corn solids by hand. The solids will be saturated with sugars no matter what you do. You can't lauter corn mash.

In a perfect world I'd find a hammer mill on ebay or Aaron equipment, or similar place, and install a recirculation pump on your still to keep the solids moving. Did you have a look at local bakeries? Maybe they can help for a bottle or two.

In an imperfect world, I'd switch to corn syrup, as even flakes are going to give you solids in your still. You're going to lose your *ss, financially speaking, if you continue down the path of 11 plato to 6 final.

Just one man's opinion. Wish I could be more helpful.

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Try using your bulk a second time, add sugar and allow to work again! The time that the corn soak will also help break down the starch.

Old timers did not boil or even heat their mash, I question if it is even worth the trouble.

I know someone sill not agree with this statement.

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Well we've figured out a temporary fix. We're having the grain crushed down a bit finer, then running it through our own simple mill we've got on an electric motor and then it gets down almost cornmeal. I'll let y'all know how things change. Even with the finer crush and doing a cook with that, the brix has gone up, so I'm excited to see what difference using the finer meal will make. The only thing I can say at this point is thank God we're also doing rum and "moonshine" as products, otherwise we really would be in for it for quite a while. I'm sure most of you know the feeling, but this is still what we want to do and quite rewarding.

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