Double Fermented Corn Mash
This is a method of getting the full flavored, sour mash taste on a initial corn mash, instead of using a sweet mash and allowing it to sour on subsequent runs. This method is more work, but it is the cheapest method for the most alcohol without using sugar in your wash.
Ingredients:
Corn
2 row pale malted barley
Target is 1.1 sg
sugar is 24% by weight from the chart
final volume 5 gallons
weight per gallon 8.3 lbs at 70°F
Initial gravity weight is 1.1 * 8.3 * 5 = 45.65
Sugar weight is 45.65 * .24 = 10.956 lbs sugar
Sugar yield corn 0.6
Sugar yield malt 0.73
Weight corn 8 parts
Weight malt 1 parts
8(.6x) + .73x = 10.956
x = 1.98119349
rounding 2 lbs per part
16 lbs corn
2 lbs malt
Grind the corn pretty fine almost like corn meal. If you have cracked corn then that is ok too. Grind the barley malt so that it is pretty much like flour.
A 25 to 30 gallon clean, trash can is about right to sour the corn. You can use a plastic 55 gallon drum too. I use the drum. Both enough room for the corn, water and foam. It may overflow from a violent first fermentation in the summer with too much heat. At 70°F it behaves, but prepare for the worst by putting the container outside or in another container, such as a wash tub, to catch spills. Make sure to cover the fermenter with a piece of screen or cloth to keep the crawlies and flies out. Make sure the screen is fastened well because the cap could try to push it off.
The target volume is 5 gallons. Start by soaking the corn with enough water to cover its height twice. The germ and bran floats to the top. Punch that down once a day for three days. On the fourth day it shouldn't rise anymore because the lactic acid is complete. It should be sour. Don't be afraid to taste it. It is somewhat like yogurt.
note: The second day it will smell rotten, so outside in the shed or barn is preferable to inside the house. This is normal. The first bacteria to start the fermentation smells really bad. The lactobacillus takes over the third day and creates an acid environment that kills the first bacteria. It just smells lightly like sour milk on the fourth day
The amount of water in the first fermentation is not enough to cook with. Cook the corn in the biggest pot available. If all you have is a 20 liter pot the I suggest two batches. I would not try to cook this on an electric stove. It is almost guaranteed to burn on the bottom. Use a propane burner such as a Cajun Cooker if available. I use a steam wand from a pressure cooker.(another post has the picture)
Add enough water to the corn to bring the volume to 10 gallons. Add about 1/4 lb of the finely ground malted barley. The pre-malting helps to keep the gelled starch from thickening to much. The acid in the corn aids the malt in it's conversion because the amylase works more efficiently in an acidic environment. Also, the lactic acid coagulates the non-water soluble proteins and helps filtering and clairfication.
It may seem like a long time but I have found that the longer you can keep the corn at gelling temperature, which is at or above 180°F, the more conversion it is capable of. Getting as much dextrin conversion as possible is the key. Another thing that the lactic acid helps is breaking apart the albumin which glues the starch together, so there is more starch available for conversion.
After the cooking allow the stuff to cool to 165°F. Transfer the whole thing to a cooler that has a lid. Allow it to continue to cool to 154°F. Add the rest of the malted barley flour. Stir this in well. It should immediately start getting thinner and easier to stir. Once it is all stirred in, close the cooler and let set until it is cool enough to touch easily. This is a long time.
Remove a small amount of the cooled wort and taste it. It should be nice and sweet and have a pleasing sourness to it too. If it is not sweet then something went wrong.
You should check your conversion with a bit of drug store, tincture of iodine. Put a couple of drops of the iodine in it. The color of the iodine will tell you what is going on. If the color is purple or black or a deep blue the there is unconverted and un-gelled starch. If the color is a deep rich brown this is ok if the stuff is sweet. It just means there is dextrin in it that didn’t get converted. This happens and is no problem. If the color stays red, then you have completed success. I seldom get a complete success.
If the iodine was not black or deep blue, then it is time to filter. The easiest way I have found is to get some material from the fabric store called monk’s cloth. I usually get the natural unbleached kind but bleached works good too. Measure and sew the monks cloth into a bag that will fit, with the edges overlapped over your big trash can or plastic 55 gallon barrel. Place the bag in the container and tie the edges firmly around the top. Pour the corn mash in the bag and let drip. Eventually it will all go through. If it is stubborn and stops up the bag, then stir it and free it up on the bottom. I eventually squeeze the rolled up bag to get the most liquid out as possible.
Ok so we have a container of sweet and sour corn wash. Check the specific gravity. Is it at your target? Is the volume more than 5 gallons?
Note: If you had a brown iodine test, you may consider fermenting what you have. The enzymes have not been denatured and should keep on working as the fermentation goes on. If you had red results, then additional boiling will increase the sugar content but denature the enzymes.
I prefer to sticking to the plan, so a bit of water reduction is at hand. Put all the liquid back in the pot and boil until the volume is 5 gallons or so.
Check the initial gravity again once it is cool. I hope you hit the target but if you don’t it will ferment all the same.
Pitch yeast. This stuff usually goes crazy. Yeast loves the nutrients in this stuff and the acid also. Once the fermentation slows down, this stuff keeps bubbling forever. I wait until the trub in the bottom is settled. I have never gotten it to settle much less than 10% the height of the liquid. I rack it off the best I can but it is just a personal preference because I usually distill with a submerged element. It really doesn’t make a difference.
This is the first batch.
The second, and any successive batches, change in process from the first. Instead of souring your corn, you mix the corn with hot back slop. Use 1 quart of back slop per pound of corn. This should put the corn near 154°F. Add the ¼ lb of barley malt, top up with water and cook. This is a compromise of sour mashing, because the acid will come from the back slop and it will continue to sour. If you use all back slop then the flavor degrades too quickly and you may be limited to half a dozen batches. Using a combination of back slop and water allows the run to continue forever.
The process is the same after the cooking part.


I had it in my head that the main issue was going to be the grain solids sticking to the hot base, I had this issue before when doing DWWG and a mash with rice in it. As it turns out the main issue was the fact that the mash got really viscous once it starts to get hot, it went like wall paper paste. The false bottom although it worked at the start keeping the solids off, obliviously had no affect once the mash thickened and the mash burned and tripped the thermal switch.
