OG different than calculated …

[Mr_Beer]

Trying to do a Mitchner Bourbon clone
Water 14 gallon
Corn 79% 26.8 pounds
Rye 11% 3.75 pounds
Barley 10% 3.4 pounds

Using BrewersFriend the calculated OG should be 1.072
Used enzymes to promote starch conversion.
Time in mash pot was about seven hours and iodine test indicated starch conversion.
The measured OG for the batch was 1.042.

I am fairly careful in my procedures and process.

Why is my actual OG so different than the calculated OG based on the grain bill?

My sense is that I did not allow enough time but I would like the opinions of others in this matter.

[Salt Must Flow]

What was the grind on your corn? Often people don't grind it fine enough and get a lower conversion rate. There are some other exceptions for corn if I recall correctly. For instance I recall it takes longer for corn to gelatinize and get the starch extracted.

[OtisT]

Did you add 14 gallons of water to the grain bill listed, or did you add water and grains until the total volume of you mash was 14 gallons? If the calculator/recipe is assuming 14 gallons total for you mash (grains plus water) and you added 14 gallons to the grains, your SG would be lower than expected because the mash is thinner. This could explain your difference.

Most recipes I am familiar with refer to the total mash volume, not the amount of water added.

[howie]

iodine test can be misleading.
maybe you only converted the starch you released, maybe you left tons of starch still in the grain? ( time,temp,PH,enzyme or milling errors)
also, i don't think that the iodine test can tell the difference in between fermentable & unfermentable (dextrins) sugars.

[Mr_Beer]

In answer to the initial responses...

The corn was ground very fine -- almost meal.

My notions were that water is separate -- 14 gallons and with the grain then 17 gallons total. That does explain some difference. That makes a reasonable difference and I did not understand the usual and customary way to express the amount. Good catch and thanks for the explaination.

I may have left starch in the grains -- the question is why -- too short a time frame or ??

[Dancing4dan]

Trying to do a Mitchner Bourbon clone
Water 14 gallon
Corn 79% 26.8 pounds
Rye 11% 3.75 pounds
Barley 10% 3.4 pounds

Using BrewersFriend the calculated OG should be 1.072
Used enzymes to promote starch conversion.
Time in mash pot was about seven hours and iodine test indicated starch conversion.
The measured OG for the batch was 1.042.

I am fairly careful in my procedures and process.

Why is my actual OG so different than the calculated OG based on the grain bill?

My sense is that I did not allow enough time but I would like the opinions of others in this matter.

Not sure what mash process you used for the corn or what grade of corn was used. Both are important.

Feed grade corn can have lower yield than you expect. Because of the low carbohydrate corn I was seeing in feed stock I pay the extra for flaked corn or corn meal. Costs more but the yield is solid consistently and I get to eat some polenta

With a 79% corn mash I would cook the corn to soft before adding any other grains. Grind it down to corn meal first. Especially if this was feed grade cracked corn.

Once the corn is cooked down to soft bits that you can crush easy between your fingers then add your grains and enzymes after the temperature has fallen to enzyme temp.

[Mr_Beer]

To elaborate on my process...
Heat water to 182 F
Add SEBStarHTL -- about twice what is recommended to compensate for age of enzyme even though it is only about 4 months old.
SEBStarHTL has a published temperate range of 176F-194F. Seems I am in the sweet spot temperature wise.
Add corn that has been crushed fine -- almost meal. Use stirrer to mix while adding.
Insulate mash pot so temp drops slowly
Stir every 10 minutes with paint stirrer on drill. Mixture is not thick or porridge like.
Add malted grains at 155F
Temp keeps dropping slowly
Add SEBAmlGL at 140F

Since the mixture was fairly thin, my notion was that the enzyme had not denatured and was active and usable for conversion.

And now my inexperience is evident. I do not know feed grade corn from any other. I bought 'clean corn' from the feed store and I believe it is intended for animal consumption. No rocks or debris -- just corn. Then I grind it.

A little research ... "More than 93 percent of dent corn is used for animal feed. It is also used raw in industry. White dent corn has a higher starch content than yellow dent, so it is commonly used in human food products. Dent corn also fuels cars and makes plastics, adhesives and starches."

Checking with the local feed store they have neither corn meal or flaked corn. Will have to locate a source for the future to try but any notions of availability would be appreciated.

So a recommendation is to 'cook' the corn at an even higher temp? And then add the enzyme?

I am doing an identical second batch this AM and will let it sit for longer period to see if I get better OG.

Thanks for all the help so far.

[subbrew]

Your method seems sound. I would have run the water temp up to 195 or so as it will drop when you add the corn. Did you take a temp after adding corn? I am wondering if the temp fell to the 170 or 165 range?

You might try what I do but I don't see it as better. I put the high temp enzymes in as the water heats, say 165. Then about 170 I add the corn but keep the heat on. I stir and heat until the mixture is 192 or so, then cut the heat and cover/insulate. I leave it be for a couple of hours and by the time I come back it is very liquid. Put that in the fermenter and do another batch. By the time do three batches I have 60 lb of corn in the fermenter and the temp is usually close to 150 or so that with just a bit of stirring I can get it to the right temp to put in the malted grain.

As for finding flaked corn, also ask for rolled corn, both names are used. If you can find a farmers coop or feed mixer that delivers bulk feed to farmers you should be able to find flaked corn. If such a place doesn't have it they might be able to direct you. In my area whole corn is about $12 for 50 lb bag and flaked it $14 so well worth going to flaked.

[ShineonCrazyDiamond]

Unless you're keeping heat on the corn and actually cooking it... Water needs to be a solid 212 furious boil. Corn will bring that down to about 185 +/- 5. Add BOILING water, mix, throw in enzymes. Let it sit for a while.

[higgins]

I start my corn based mashes in the evening, taking just a couple of hours and finishing by 9 or so.

I boil my water (206F, 1/2 gal per lb of corn) and mix into the fermenter (30 gal HDPE barrel) with the cornmeal.
Then I mix in the HTL enzyme and leave it overnight.
The barrel sets on a piece of foamboard insulation and is wrapped up tight in a double layer of old quilts.

In the morning it is right about 150F or so. This gave the corn about 10 hours between 180F and 150F.
I still have 1/2 gal per lb of other grains to add - I can use it hot or cold for adjusting temp if needed.

When the temp is right at 150F I'll add my other grains and mix, and it usually settles around 145F for the main 2 hour mash.

[Mr_Beer]

First, I definitely appreciate folks sharing their process for me to compare against. Very helpful.

Second, I will be searching for flaked corn -- sounds like I am not asking the right questions.

Third, as they used to say, RTFM...
My second batch worked well and came out within .002 of the OG range predicted by BrewerFriend. Turns out that my corn conversion with SEBStar HTL was going well but I shortened the time for the SEBAmlGL. Apparently SEBAmlGL needs hours (upwards of 10+) to work away at the conversion process according to the spec sheet. Patience is not my strong suit -- but you folks all helped me determine the error of my process.

Thanks again for the help.

[Homebrewer11777]

Hey late to the convo but just wanted to comment that all the software packages I've seen that are designed for and used by beer brewers call for measured amount of mash water (and split that water into strike and sparge amounts). If the recipe called for 14 gallons of water that is what it wanted. Some software will then give an estimate for expected total mash volume to make sure it is going to fit in your mash tun.

Also if using beer brewer software most don't seem to have cracked corn as ingredient. Some have corn grits. Or you can create an ingredient in others. I'm using 30 PPG for my cracked corn, even after grinding it pretty fine, and this seems to work out fairly well. That is substantially lower than brewers flaked corn which Brewer's Friend estimates at 40. So if you put flaked corn in the recipe but substituted cracked corn...

You can try to compensate by using a different brewhouse efficiency, each software package is a little different on what brewhouse efficiency means and none expect you to ferment on the grain. Might be good idea to put some of the tried and true recipes from this site into the software you are using and see if you get expected OG prediction.

[Homebrewer11777]

OK I give up. The tried and true recipes don't include enough or the right information to enter them into beer brewing software. But like I said a spreadsheet seems to work just fine.

[Mr_Beer]

My process is truly home grown.

Great info regarding the PPG you use for cracked corn versus BrewersFriend. Thanks.

It took me a while to actually understand that the limiting factors for recipes was the capacity of the mash pot and the capacities of the fermentation vessels and associated grain absorption. Efficiency is now fairly far down on my list of concerns as long as the OG is lower than 1.07x. Higher OGs tend to limit the yeast used and possibly require the starters. Using enzymes I typically reach the BrewerFriend OG numbers within .003 or so. Close enough for me.

I have sort of standardized on US-05 yeast. Discussions and reading have indicated that the cost and agravation of starters is probably not useful with dry yeast and larger volumes. At this point I just add more yeast instead of a starter using BeerSmith yeast tool to compute the amount.

My spreadsheet 'assistant' is essentially a recipe book along with various metrics that follow the recipe from start to blending and ageing. Not great but is is a good reminder and checklist as a recipe is being formulated.