My effort at malt corn production:
Figure of Germinated Corn
Figure of Single Kernel
I steeped 5 lbs (in a mesh bag) for 24 hours in 1% hydrogen peroxide, just enough to cover the kernels, in stainless steel pot, with lid, at 30 deg C. Corn was not rinsed nor soaked other than this single steep. They were drained (saved the steep water, maybe will use later as yeast nutrient in the ferment) and stored kernels in a stainless steel pot with a lid (so no light) for several days at 30 deg C. The above image is after 4 days. The H2O2 was used to both sterilize the kernels and provide some oxygen. I did NOT use drug store H2O2, which has some sort of preservative. I diluted 29% commercially available hydrogen peroxide down to 1%. After four days, there was no mold nor funky pukey smell, just "corny" and organic. I’m certainly not the first person to try H2O2. There are a number of papers discussing this, including one from early last century! One of these old papers also provided strong evidence to not over-soak the kernels, since this actually removes the soluble nutrients that the seeds need to germinate. I love this hobby because of the research aspect!
Figure of Cross sections
Above is an image of cross sections of ungerminated corn, and kernels after different days of germination. The middle one was germinated until the rootlet was about one inch and the acrospires could be seen growing under the hull, but were short and did not exit the corn hull (~3 Days). The right kernel was allowed to germinate until the acrospires were about 1.5 inches long (~4-5 Days). The germinated samples had been dried prior to these pictures, and the rootlets and acrospires were removed. As described in the literature, the embryo is larger in the germinated kernels. It is important to note that even in the kernel with a long (1.5 inch) acrospire, there is plenty of starch left. I’ve found references in the peer reviewed literature which state that 3 inches is the ideal acrospires length for maximal corn amylase production. This is probably dependent upon the type/strain of corn. I plan on looking at a cross section of corn with 3 inch acrospires to see how much starch is left.
As any scientist would do, I tasted different parts of the germinated kernel. The acrospire was nasty! Very bitter and grassy (as has been mentioned here on HD, leaving the acrospires makes a grassy beverage). I’d personally not want this in the final product. I also removed the embryo and tasted that. It was a pleasant surprise, since I anticipated grassy bitterness. It was a little nutty, reminded me of unsalted sun flower seeds. Also, a very slight hint of sweet, which is expected since the amylases begin to hydrolyze some of the starch around the embryo into sugar, which is taken up by the embryo to energize development. I think this will add to the flavor of the product. The roots tasted as bad as the acrospires, grassy, maybe with nuances of dirt (which is odd since this was all germinated in a stainless steel pot). Finally, chewing on the endosperm starch from ungerminated kernels produced a gritty corn meal material that tasted like, well, corn meal. On the other hand, the Day 4 endosperm was quickly chewed into powder, which, upon longer chewing, tasted sweet (as expected, from amylase in saliva). All in all I think I’m ready to mash! The malted corn kernels were "kilned" via air drying in the dark as a shallow layer in a large tray, with a fan blowing over the surface. Took about three days, the end point was when the rootlets and asrospires were withered and easily broken off of the kernel.
Figure of Crushed Corn
Also, there is an important observation stated on the parent site (by Ian Wisniewski: “
By splitting a grain open with a fingernail, a small amount of the endosperm can be rubbed between the thumb and forefinger. If this leaves a fine white powder mark, it confirms that the starch (in the form of barley flour) is ready for kilning. A lack of white powder indicates the starch is still enclosed by cell walls and protein.”). The starchy part of the kernel in the untreated sample was very hard, while the starchy part of the germinated kernels could be crushed into a powder. The picture above is of material that I used my thumbnails to scrape and pulverize; the untreated remained essentially as big pieces of material, while I was able to turn the germinated corn starch into powder. This suggests to me that the malting process was relatively successful (at least according to the above quoted passage).
Next step, the mash! I plan on gristing the dried malted corn kernels (after sifting out the dried rootlets and acrospires) into a fairly fine powder. Although the embryo part of the kernel will not add to the carbohydrate component of the mash/ferment, the ground up embryo may add fats and other compounds that may serve as yeast nutrient or maybe add some character to the final product. More later!
Bobdoe
The Bluegrass Biochemist - Converting malted corn mash using salivary amylase from the spit of Kentucky virgins
More, give us more.
