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Jun 08, 2022 View:

Gelatinization and conversion of Corn

Hi All,

I'm not getting to the OG that I would expect from my Bourbon.   I've tried a few variants on technique, and soak time, but still haven't managed to quite get where I want to be.  

Currently I'm using the corn in a cracked level of grind... some flour with the remainder being approximately the size of a normal barley grind used for beer.  I chose that, planning on trading some efficiency for ease of working.   I'm steep cooking it, raising the water to 210 and then adding the corn which brings it to 200 while stirring to avoid clumping or dry spots.   I've been experimenting with various soak/cook times, including 1 hr, 90 minutes, 2 hrs, and even an overnight insulated cook of 9 hours I read about on another site that resulted in a stuck sparge and a very long day.      My first runs I was trying to use just the enzymes in the malt... the math said there should be enough diastatic power, but I ended up with a 1.02 which was frankly unacceptable so I purchased high temp alpha and beta, as well as regular temp alpha.  (suspecting the malting of the grain was happening a few degrees too high and denaturing some enzymes)  I'm fairly consistently getting 1.04 with the enzymes, but I'd be expecting to be more in the 1.05/1.06 area if everything was happening properly.   

My next avenue of improvement I can think of, is that I need to be grinding more finely.   That leads me to my first question.   How large a hole do you guys use in the filter on your mash tun use when working with the more fine grinds?   Did you have to make modifications to your equipment compared to mashing malt based whiskey?  My second question... is there anything obvious I'm missing?    I've been a brewer for my whole life, but not worked with corn till much more recently.  I know unmalted corn is more of a challenge, but I'm really hoping to dial in my efficiencies a bit.  




I'm  surely not an expert on corn but there is a  great video on you tube by a guy named pinto shine all about using enzymes . It's a small batch but the science is the same . Dunno it might help ya . 


I'm  surely not an expert on corn but there is a  great video on you tube by a guy named pinto shine all about using enzymes . It's a small batch but the science is the same . Dunno it might help ya .It's called mashing 100% corn with enzymes. 


Moving from roller milled coarse crack corn to hammer milled “coarse flour” increased our product yield by 20%.  We expected a chance, but it was a shocking improvement.

No other change, our typical SOP is steam injection with a 90 minute hold above 200f.

Is your tun heated/jacketed?  Do you have the ability to cook?  If not, going finer may be your only option.  Keeping your barley husk intact will help lautering, but lautering corn is always a nightmare (so don’t bother trying).

Also consider fermenting on the grain if you are utilizing glucoamylase.  While you won’t see a change in your starting gravity, you will end up with a higher final product yield due to enzymatic starch breakdown.


@Hudson bay distillers I appreciate that, I am aware of Pintoshines vids.   I've been reading the stuff on for a while, both during my learning process and during the few years I've been in process of opening up. 


@slick city distillers, thanks much!  that would make a lot of sense.   No, my tun isn't heat jacketed.   I'm using converted stainless steel barrels, so I have direct heat, but the thinner walls of stainless barrels means I have to use a bit of insulation to keep temps within the gelatinization range, when I attempt the longer time frames compared to purpose built stainless in a nearby friendly location that has been willing to talk with me.   I have 2 tuns, 1 with a finer mesh and the 2nd with a wider mesh.   I do have the ability to cook, but only via 2 methods.... either I can keep a rapid spin going via a stainless stirrer powered by a 1/2 inch drill so that I can keep direct heat on, or else I can insert a copper coil filled with heated water into the mash tun.  Thus far in my experimentation I haven't yet tried the second... just built what is needed for it.    So far I haven't had trouble keeping temps... which is a point of discouragement on why I'm not getting the results I'd expect from the math.

Reply:4 hours ago, Silk City Distillers said:

When you say taste differences between grain in distillation and Laudered distillation are you  talking about scorched taste.

Reply:On 9/4/2019 at 9:09 AM, Hudson bay distillers said:

We're just starting with corn (2 years in with potatoes, and making great vodka from them!).  We buy flaked (pre gelatinized) corn, and mill it to a flour just a fair bit finer than corn meal, but not all the way to bread flour.  We have a jacketed mash tun, and use Alpha, Beta, and Bioglucanase enzymes (no malted grains).  We're getting pretty consistent Specific Gravity of 1.08 (10.4% potential alcohol).  We also have a jacketed still, and distill on the grain.  Take everyone's advice about not trying to lauter corn - you'll die trying, and it won't benefit you much (unless you have a $20k centrifuge separator).


Jon - how many gallon beer ?

Reply:On 9/13/2019 at 7:19 AM, Roger said:
Reply:37 minutes ago, JonDistiller said:
Reply:On 9/16/2019 at 6:31 PM, glisade said:
Reply:On 9/3/2019 at 3:49 PM, Hudson bay distillers said:

 Your welcome Jon glad you got it working.