Starch Conversion Using Cracked Corn

Jarreau82

I’ve read some other starch conversion threads, but I’m still stumped.
Backstory: I started using a 120qt igloo cooler as a mash tun. I made a pretty slick drain manifold out of ½” copper tubing that works really well at separating wash from grains. I’m able to drain my grains dry using this setup along with a small transfer pump. I’ve used this setup 3 times. First attempt was an all grain Irish whisky mash which came out great with no issues. Second attempt was honey bear burbon, and I had an idea to use cracked corn from the feed store with no other milling. Had a problem with starch conversion on that one, didn’t reach by target OG. I thought somehow I had denatured some enzymes on this one, or maybe I didn’t have enough DP to convert even though my math worked out. So third attempt I put together a mash bill of cracked corn, pale malt, and dark wheat malt. When I did the math to reach an OG of 1.07 on a 20 gallon batch I’d need 36lbs of cracked corn, 10lbs wheat malt(DP:160), and 10lbs pale malt( DP:140). That’s 2.8lbs of grain per gallon with 46.43L so I should be able to get full conversion. Just as a check I ran these numbers through an online calculator, and the OG came back much lower at around 1.05. So I adjusted the numbers to get to 1.07 and they were: 50lbs cracked corn (well, corn grits was the closet option on this calculator), 15lbs wheat malt, and 15lbs pale malt. 49L so it should fully convert. 4lbs per gallon seems high but the corn is cheap and I was thinkin I’d have a hard time getting the starches outta that cracked corn so I rolled with it. I’m using filtered tap water that I filter myself.
My mash procedure:
The night before I poured a 50lb sack of cracked corn into the mash tun and added 4 gallons of boiling water to preheat for about 15 minutes. Next I transferred 11 gallons of boiling water from the HLT to the mash tun. The mixture was at 191F. I added sebstar high temp enzyme and closed up the mash tun to let it sit overnight. The next morning (about 11 hours later) I opened up the mash tun and checked the temp: 170F. So I was thinking I should have gotten plenty of starch from the cracked corn holding that temp for so long plus the sebstar. At this point I stirred till the temp reached 158, then added my malts, bringing the temp down to 148. pH was 6. I closed er up and stirred every 30 minutes. 2 hours in, an iodine test indicated starch was still present. I continued to check every thirty minutes, and every time starch was present. 5 hours in my temp was down to 139, so I added 1 gallon of hot water to get back up to 145. I let it sit for another two hours, but still getting starch positive results. At this point I figured I got all I was gonna get so I pumped off the wash into the fermenter. I pumped off 5 gallons that came off at 1.091. Next I added 12 gallons of hot sparge water, let sit for about 15 minutes giving it a good stir every few minutes. Pumped that off and it was coming out of the mash tun at 1.063. I added in another 3 gallons of cool water which got me to 20 gallons with an OG of 1.052. Not bad, but I did not get full conversion. I cooled the wash down with an immersion chiller and pitched distillers yeast, fermax nutrient, and glucoamalayze. It’s working off now.   
Any idea as to why I didn’t get complete conversion? Could it be a water chemistry issue? This has only been an issue since bringing cracked corn into the equation. Could there be chemicals in the cracked corn preventing starch conversion? It’s supposedly tripled cleaned with no preservatives says the feed store.  Also, will unconverted starched give off flavors in the distillate? I appreciate any advice.
Thanks

StillerBoy

Question..  How do you think the starch in the un-cracked portion will be exposed to the HTL..   Are you of the view that the HTL will extract the sugars from the starch of the un-exposed   portions..
Mars" I know quite certainly that I myself have no special talent. Curiosity, Obsession and dogged endurance, combined with self-criticism, have brought me to my knowledge and understanding "
– Albert Einstein

Jarreau82

I was thinking the high temp enzyme would help gel the cracked corn. Will it not have that effect? I was trying to avoid milling the corn so that drain manifold wouldn't give me a stuck sparge.

Salt-Must-Flow

Technically the hot water is what pasteurizes the grain, leaches carbohydrate from the starch cells and thickens the mash. This thickening is called Gelatinization. The enzymes convert the available starch into sugars. If the grain is too coarse then the water cannot extract/leach out the carbohydrate/starch for the enzymes to convert into sugars.

Jarreau82

Is cracked corn just too coarse to gel then? Any idea as to why the starch that was present didn't fully convert to sugar?

Demy

My opinion is that the cereals must be well ground (not a flour but almost), be cooked enough to gelatinize .... this is the ideal ground for the action of enzymes.

Salt-Must-Flow

Here's a topic I found real quick.

still_stirrin

Exposure.
Cracked corn remains mostly “encapsulated” in the kernel.  The endosperm (the “grain material” that feeds the germ when growing) is protected by the epidermis, or outer seed shell.  Cracking the kernel exposes a little portion of the endosperm, but a fine grind into a corn meal exposes most of the inner carbohydrates to the water.  
There are natural enzymes in the kernel that will begin starch reduction to provide the energy nutrients that would help the seed germinate and grow.  Ironically, if you malt the seed grain, then this germination process will begin the conversion process too.  Gelatinization likewise begins the carbohydrate reduction process and this will turn the corn meal into a “corn pudding”.  High temperature gluco-amylase enzymes help to significantly reduce the long chain starches and thin the pudding into a “soup”.
So, grinding the corn beyond simple “cracked corn” will help with the enzymatic activity which will ultimately help with starch to sugar conversion.  It “exposes” the endosperm to the enzymes which will break down the carbohydrates.  Keep in mind too, that proper conditions also are necessary to assist in the reduction.  
Proper pH and temperature are important.  Also, hydration, or the right amount of water per pound (or kg.) of grain is also important.  Certain enzymes favor a “stiff mash”, enzymes like the acidifying and protein reduction enzymes.  Beta amylase also like the mash “thicker” than the alpha amylase enzymes do.  So, the correct water ratio is always a compromise to the mash process and how you intend to develop the mash profile.
Make sense?
ssAttention new distillers: Cranky's spoon feed info
My LM/VM & Potstill: My build thread
My Cadco hotplate modification thread: Hotplate Build
My stock pot gin still:  stock pot potstill
My 5-grain Bourbon recipe: Special K

Jarreau82

SS - Good explanation. Yes, it makes sense. Looking back, even after sitting overnight the cracked corn pieces were still intact and pretty firm, and the liquid was very thin. I'll try milling the corn in the future to increase exposure. You mentioned using the right amount of water per pound of grains. What ratio do you suggest? Thanks for the insight.

squigglefunk

i could never get cracked corn to get anywhere near cooked using the overnite boiling water soak. A lot of wasted starch.

Ben

I did a bunch of work on this and documented it here: viewtopic.php?t=84742
Ultimately I found pretty good efficiency running cracked corn through a roller mill set at 0.030" gap, and with use of rice hulls was able to sparge like you are doing with good takeoff rates. If you take the corn down too far it will make sparging difficult.
Water chemistry is unlikely, and more difficult to deal with accurately. Try a grind on the corn, and ensure you are giving adequate rest times at gel and mash temps.:)

Jarreau82

Thanks Ben I think I'll give that a try on the next one.

still_stirrin

I gelatinize corn separately from the main mash.  So, for the corn (milled to a cornmeal consistency), I bring 2-1/2 gallons (10 quarts or approximately 9-1/2 liters) of water to a simmer on the stovetop.  Then, I “dough-in” or stir the 5 lb. (approx. 2.3 kg.) of cornmeal into the hot water.  Stir this regularly to keep the heat uniform and breakup any “grain balls” that may clump together.
While this is is gelling, I start the main mash in the mash tun.  I’ll “underlet” the false bottom screen with mash water at strike temperature, roughly 160*F (71*C), and then begin to dough-in the other cereal grains (malted barley, wheat, oats, etc.) and add hot water to bring the temperature to saccarification temperature (150*F/65*C).  The amount of water will be roughly 1-1/2 to 2 quarts per pound.  The mash will be thick enough to hold a spoon upright, yet it is “stir-able”.
I’ll let this mash set, again stirring occasionally to make the temperature uniform throughout the mash tun.  After an hour or 2, I’ll dough-in (add) the “corn pudding” from the stovetop, again stirring the mash to homogenize the mixture.  Now, it may require the addition of more heat, so I’ll again add hot water (at 170-175*F/77-79*C) to bring the mash back to 148-150*F.  Often this will require another 1 to 1-1/2 quarts per pound of grains.
By this last addition of water, the total water in the mash will be 2 to 3 quarts per pound, not counting the amount of water used to underlet the false bottom.  That amount would add another approx. 1/4 to 1/2 quart per pound.  So you can see, the mash begins thick and progresses to a much more “thin” mash.  
Now, I choose to lauter (sparge) my mashes, so I’ll add even more hot water as I runoff from the tun.  But many here do not lauter their mashes, so they’ll have 2 to 2-1/2 quarts per pound, or approximately 2 lb. per gallon (or slightly thicker).  Keep in mind that the starch conversion enzymes prefer a liquid environment over a “pastey” mash, so a thinner mash will help conversion but give you a slightly lower OG (more water per pound of grain) yet esult in more extraction of the potential sugars in the fermenter.
Whew … I’m out of breath again.  But, I hope this lesson will help you and future all-grain brewers.
ssAttention new distillers: Cranky's spoon feed info
My LM/VM & Potstill: My build thread
My Cadco hotplate modification thread: Hotplate Build
My stock pot gin still:  stock pot potstill
My 5-grain Bourbon recipe: Special K

Salt-Must-Flow

I gelatinize corn separately from the main mash.  I always wondered if one could pressure cook their cracked corn to gelatinize it thoroughly then run the mushy grain through a dedicated garbage disposal to break it up or by some other method if need be.
This was the idea I had rollin around in my head:
1. Thoroughly rise/flush the cracked corn. Removes foreign matter, floaters and fine debris.
2. Soak it in water overnight to aid in hydrating the corn. Couldn't hurt.
3. Pressure cook the corn for 45 min to 1 hour at 15 psi to gelatinize. Scorching could be a reasonable concern, but there's always ways to keep that from happening.
4. Blend the gelatinized cracked corn into mush. Drill & mixing paddle? A dedicated garbage disposal? Other methods perhaps.
You could say just mill it, but I don't own a mill. Buy a mill and do what is conventionally done ... I get it. I just had this idea stuck in my head for a while. Many years ago I made a giant margarita machine out of a big ol Igloo beverage cooler using a garbage disposal and figured if it would grind up ice, it should chew up soft mushy corn. I own a really large pressure cooker, but a keg can easily be converted into a pressure cooker too. Cornmeal would be easier as it would be just like making grits I suppose.

JLP-IV

Some reading on that Salt  

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Especially the post on page 2 by Halfbaked
viewtopic.php?t=35600

Salt-Must-Flow

That's a good topic, thanks. What Halfbaked was outlined is canning (pasteurization) instead of pressure cooking (sterilization). Much to think about. Thanks again.