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I have used cornmeal 5 times now for an all grain whiskey mash. I decided on cornmeal as opposed to cracked corn because of the higher yield despite its other problems such as scorching and straining after the fermentation. It has always converted and given me a 1.056 to 1.059 OG. Let me tell you my procedure and my proposed changes. You tell me what you think of the proposed changes.

The grain bill consists of 14# cornmeal (65%) + 4.25# flaked rye(20%) + 3.25# 6 row barley (15%). All this cooking and mashing is done in a 15 gal SS beer keg

My procedure to date:
Heat 7 gal of treated brewing water to 170F
Add cornmeal. Stir to remove lumps. Temp drops to 160F
Add 1 1/2 tsp alpha amylase (or 3 oz of barley) to pre-malt for 20 minutes
Bring to a low boil on medium burner stirring constantly
Keep at simmer on low burner for 15 minutes (or more) stirring occasionally
Stir in 4.25# flaked rye
Add 4.5 gal of 75F treated water. Stir. Temperature dropped to 140F (was targeting 151F so had to reheat to 151F)
Add 3.25# barley. Stir. Temp dropped to 150F
Put lid on and cover with blankets and leave for 1 hr. Stir it. Leave another hour. Temp drops to 145F in 2 hrs
Force cool to 85F. Scoop out 12 gal of mash into buckets and add 6 Beano tabs and pitch yeast.
Ferment at 75F until SG = 1.000 (7.5% abv)
Strain 9 gal into still and strip to get 30% abv low wines. Then spirit run

Like I said this has always worked but it scorches like a S.O.B. and is a pain to stir while cooking the cornmeal. So I propose these changes:

Since my target strike temp was low for the mash (140F .vs. 151F). Next time I will cook the corn with 7.5 gal of water (instead of 7.0 gal )which should make it a tad easier and add only 4.0 gal of water (instead of 4.5) after cooking which should bring the strike temp up. The biggest change that I want some feedback on is to do away with the pre-malt step and add the cornmeal to 7.5 gal of boiling water (210F) which should settle at around 200F to 205F. Cover, insulate and "cook" the corn this way with no burner , thus no scorching.

Is the pre-malt step really that necessary and will a 190F to 200F "cook" gelatinize the cornmeal adequately?

Thanks,

Todd K.

I tried out my ideas yesterday. It was successful, sort off. I was hoping to end up with at least 1.056 gravity. I got 1.050 instead.

So instead of mixing cornmeal in to 160F then adding enzymes to liquify (pre-malt) followed by heating and scorching to a simmer, I heated my water to boil and slowly added the cornmeal while stirring with the burner still on high. It clumped horribly. As I added more cornmeal and it got thicker I put a baffle over the high pressure burner and turned the heat down. By the time I had all the cornmeal mixed in and with the burner baffled and on low, the pot was lightly simmering with no scorching. I could have just kept this simmer going while stirring but I shut off the burner, covered the pot and insulated with blankets. I let that set like that for 45 minutes. When I uncovered it the temperature was 210F and the mush was a creamy consistency. Success on that part!

Now I need to figure out why the low gravity. It could be as simple as the way I read the hydrometer the last time. Even after straining through a wire strainer the reading was between 1.056 and 1.050 because of the hysteresis from the suspended solids . I then filtered the sample overnight through a coffee filter and the reading was 1.050. My refractometer that I just got for xmas confirmed this with a reading of 1.049. Maybe it was the clumping leaving dry pockets of cornmeal. Maybe it was from using only 15% 6-row barley in the grain bill. So with these maybes in mind here is my revised plan for next time including pre-wetting the cornmeal with 1/3 of the cooking water before adding it to the remaining 2/3 boilng water and upping the 6-row to 20%. It will be a couple of years before I try this again though.
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Note: all water mentioned here has been treated with dechlorinator (sodium metabisulfite), gypsum added, and acidified to about 6.0 pH with phosphoric acid. Temperatures in () are expected temps after that step is completed.

-Heat 5.5 gal. treated brewing water to boil (210F)
-Mix 2.5 gal water with 13# cornmeal in bucket to pre-wet
-Slowly add wet cormeal to boiling water.
-Burner on high at first then baffle and reduce burner as mash thickens.
-Simmer 15 min or more on low burner stirring constantly...
-...or turn off burner and insulate and rest 45 minutes (210F).
-Add half of 3.5 gal of water to thin things a bit (165F)
-Stir handful of barley or amylase (~1 TBL) to liquify (165F)
-Stir in 4.25# flaked rye. (163F)
-Add remaining half of 3.5 gal water. (150F)
-Let cool or heat to 150F. Add 4.25# barley (148F)
-Insulate and mash 120 min between 150-140F stirring once on the hour (141F)
-Chill below 85F, Add glucodiase (6 tabs Beano)
-Ferment on the grain at 75-80F with Nottingham dry for about 10 days
-Strain and pot still 2 times

Yields 12 gal (SG 1056). Scoop out 12 gal into two buckets. Fermented out to 1.000 SG. After
straining, 9 gallons of 7.5% abv to still.

Notes: to check gravity of mash , draw 1 pint off and run through fine strainer then again with coffee filter overnight.

I think you've hit on it by pre-soaking the meal. That will definitely keep it from clumping and will also help it suspend better in the water. I pre-soak cracked corn with boiling backset and then add some alpha for that very reason.

Big R

I finished the spirit run on the two strippings last weekend. I am pleased with the results. The effect of the scorching on the first stripping did not carry over through the spirit run. I ended up with 9.5 liters (40%abv) of middles and about 2.5 liters of feints. the aroma is very aromatic, almost like a good tequila. The flavor is definitely corn. Age on some wood chips and this should turn out to be some mighty fine sippin' whiskey. Need to work on improving my yield next time. I'm thinking there may be something to simmering and stirring the cornmeal mush on a low baffled burner to improve yield rather than just mashing in, turning off burner, covering and let steep. So many variables...where to start? (rhetorical question).