10.19.2013

Extracting sugar from corn, to malt or not

Let's say one wanted to extract fermentable sugar from corn.  Is it worth it to malt it first?

I took 300 g organic feed corn and covered it in water for two days, drained it, kept it moist by rinsing it a couple times a day and allowed it to sprout (see image below).  Then, I spread the sprouted corn on the concrete floor of my basement for a couple days until the kernels lost most of their moisture and looked like they did when started (only with sprouts hanging out of them, I couldn't determine residual moisture).  I did not pull off the rootlets and ground up each batch using a corona mill.  I then ground up some unmalted feed corn from the same bag and infused each of them in 1000 g of 170F water.  I stirred both suspensions several times during the hour and filtered off the solids via mesh paint strainer bag with no rinsing of the grain bed.

malted corn prior to drying

Results
Sugar determined by refractometer.
Malted: obtained 806 g of solution with 7.5% w/w dissolved sugar, 60 g sugar.
Unmalted: obtained 730 g of solution with 4.0% w/w dissolved sugar, 30 g sugar.

For some reason the unmalted absorbed more water resulting in a smaller filtrate volume.

Pretty big difference.  The malting takes a lot of time, but almost no effort.  If you need this kind of sugar for a project, I'd do the malting.  With unmalted corn, it could be cooked for a long time to get more starch out, but then it gets gummy and difficult to filter.  I simple infusion is operationally easier.