Protein Rest/Flint Corn

Production methods from starch to sugars.

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Powder Monkey
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Protein Rest/Flint Corn

Post by Powder Monkey »

I’m looking for some collective opinions related to protein rests and secondarily to those that have experimented with the nuances of corn varieties other than yellow dent.

I’ve been distilling for about three years, mainly rum but have had some successful bourbon style products. I also homebrew beer on occasion. I operate a small farm and grow a variety of grains and look forward to experimenting with some nuances of less frequently utilized base grains. At this point my skill/process is not refined or controlled enough to eliminate the multitude of variables in comparing recipe A to recipe B, at least on a scale I could get good data from. I hope to achieve this point in the future. Thus I’m looking for opinions/experience on the subject as I move forward with experimentation.

1)How much would a protein rest effect outcome, namely flavor, with higher protein content adjuncts? For example the flint corn I grew is higher protein/lower starch. I know yeast like free N (can also be added via nutrients), I’ve also read freeing up proteins can contribute to ester/aldehyde formation (this fact(?) is the main impetus for my theory) and also read it can reduce puking. If protein potentially plays a part on flavor development (among 200 other factors), and it is a key characteristic of the grains chosen, it could be something to play with. Or maybe I’m overthinking it and this is such a minute factor it doesn’t matter.

2)How would one design that process? I can figure out ways to heat a mash but I currently do the boil water/cook corn cool to mash and ferment on grain before straining method. I could cool the corn then do a step mash, but don’t have a good way to directly heat the mash at those temps. I would envision adding in some additional distillers malt at protein rest temps 120-130F, after saccharification and “sacrifice” the small amount of potential conversion. How much would one use for this as there is no equivalent measure of “DP” for proteases.

Alternatively maybe there is enough overlap between protease and amylase activity that simply performing the mashing step at lower temp 140-142F would have enough carryover between the two.

I believe malting to full conversation of any adjunct would forgo the need for protein rest but it is much easier to grab some grain from the bin.

My attempts have been to compare recipes of 100% flint/50%flint 50%dent etc to isolate the corn nuances, but have had mixed results. Typical recipe has been 90% corn 10%distillers malt. I do add enzymes to hasten the thinning of the corn. In the future I’d like to experiment with some oats and buckwheat as well as other corn varieties.

Hopefully these various thoughts might result in some good discussion.
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Ben
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Re: Protein Rest/Flint Corn

Post by Ben »

I think if you want to successfully protein rest you are going to want to malt your corn. That will allow you to skip the gel rest and step mash it as though it were malt. I am not 100% on this. I know you don't want to mess with it, but as you said malting may completely forgo the need to protein rest.

For your step mashes there are a few ways to get to it, one would be direct heat, but scorching is a real problem with corn, try decoction mashing. Basically you pull a specific volume of the mash (the liquid and goop), heat it to a boil and add it back to the mash to hit your next temp step. This requires very minimal equipment and can add some nice flavors via caramelization. If you want maximum levels of control you can run a HERMS setup, I am blessed with one due to the brewing hobby and it is the most repeatable, easy (push some buttons) step mash.

You don't see protein rest mentioned with corn very often, I am interested in the results. Maybe this is one of the big flavor differences between malted and un-malted grains in distilling.
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I think you want the peptidase activity, so really resting in the low-mid 120's is going to be the best range, or even running one rest at 115 which would double up as a beta-glucan rest and further expose the proteins + make the gel stage easier and a second rest at 130 could be a good procedure, then get to 180 for gel (this is going to be the tough part, its going to take a huge decoction, or a HERMS or direct fire setup). Then you would have to cool to ≈145 for saccharification, add grain or enzyme, then up to 168 if you are sparging. It's a lot of steps to take on without advanced equipment, but I think it could be a really fun, involved brew day!
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still_stirrin
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Re: Protein Rest/Flint Corn

Post by still_stirrin »

Powder Monkey wrote: Sun Dec 05, 2021 3:52 pm 1) How much would a protein rest effect outcome, namely flavor, with higher protein content adjuncts? ... Or maybe I’m overthinking it and this is such a minute factor it doesn’t matter. <— Indeed the nuances will be in the noise. Or, the subtleties will below your perceptional threshold. Maybe with a very critical palette you might discern a difference in a sided-by-side comparison. But most tasters wouldn’t.

2)How would one design that process? … don’t have a good way to directly heat the mash at those temps. <— Ben suggested a decoction. That is an excellent idea for a “bottom up” step mash. It adds a lot of character while giving you the ability to heat the rest of the mash in steps.

It can be messy, however, because you’ll need to pull a portion of the mash to another (direct fired) pot to simmer and add back to the mash tun. Constant stirring will help avoid scorching the decoction mash while heating it.


I would envision adding in some additional distillers malt at protein rest temps 120-130F, after saccharification and “sacrifice” the small amount of potential conversion. How much would one use for this as there is no equivalent measure of “DP” for proteases. <— I don’t know how you would do this, as the protein rest should precede the saccharification, not follow it. Are you thinking of adding malt on “the way down”, as your mash is cooling from saccharification? If so, that is wrong and would result in a starchy, cloudy mash.

Alternatively maybe there is enough overlap between protease and amylase activity that simply performing the mashing step at lower temp 140-142F would have enough carryover between the two. <— Beta amylase WILL WORK at the lower (140*F) temperatures, but it will be very slooooooow. I doubt you’d want to wait for complete conversion of all starches at that temp because it could take hours/days. 145*F to 150*F is nearly ideal for the beta amylase to get it’s job done.

I believe malting to full conversation of any adjunct would forgo the need for protein rest but it is much easier to grab some grain from the bin. <— Sure! If you have the opportunity of your own “produced” grains, then it is ideal to learn how best to use them. It’s what I do with cereal and feed grains produced by my family farm. It gives my products “personality” and adds to the personal pride.

Malting wheat is easy and relatively quick (3 to 4 days), but malting corn will take a few days more. The processes are the same, however. There are several threads on the website to discuss “how to”. But malting does not eliminate the need for a protein rest in high protein content grains, wheat for example. But malting does help reduce the proteins significantly, breaking them down for carb reduction. Malting does improve the cereal grains’ flavors and that will help your distiller’s beer.


My attempts have been to compare recipes of 100% flint/50%flint 50%dent etc to isolate the corn nuances, but have had mixed results. Typical recipe has been 90% corn 10%distillers malt. I do add enzymes to hasten the thinning of the corn. In the future I’d like to experiment with some oats and buckwheat as well as other corn varieties. <— Oats and/or buckwheat would indeed add “something different” to your bourbon beers. Give it a try and see what you think.

I use 5% flaked oats to my bourbons (see the Special K recipe in my signature). It definitely adds a “smooth mouthfeel” quality to the spirit’s character. And buckwheat will give you an “all grain bread” character. But again, keep it at 10% to 15% maximum. You’ll want the corn to dominate a bourbon’s flavor profile. And don’t be afraid to increase the malt slightly too. 15% to 25% will help balance the “sweetness” from the corn’s character.
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Re: Protein Rest/Flint Corn

Post by Powder Monkey »

Thanks for the responses. Ben I appreciate the decoction tip. I currently have an electric set up so burning can be a problem. I had the propane turkey burner in the past so probably can rig something up. I’ll just add to my equipment desires for now...

Still stirrin-lots of good stuff you covered. Thanks for taking the time. Now seems like malting might be easier than the extra steps/mess. Only way to decide is to try it. I have malted barley and a little bit of wheat with reasonable success.

My thought was adding some malt “on the way down.” Not knowing protease “power” I don’t really know how much would potentially be effective. My hope was a small amount 2-4% of distillers malt would be effective without leaving enough residual starch to cause an issue.

Thanks for the guidelines on starting places for adjunct grain percentages.
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Re: Protein Rest/Flint Corn

Post by Bee »

Is it better to use hulled buckwheat?
Do the hulls leach tannin at corn gelatinization temps?
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still_stirrin
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Re: Protein Rest/Flint Corn

Post by still_stirrin »

Bee wrote: Fri Dec 31, 2021 6:44 am Is it better to use hulled buckwheat?
Do the hulls leach tannin at corn gelatinization temps?
Yes, barley (or buckwheat) husks will leach tannins at corn gelatinization temperatures. So, the amount of tannins will depend on the percentage of the grainbill that the wheat or barley is … keep it low and the tannins can be dealt with during cuts.
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Re: Protein Rest/Flint Corn

Post by Bee »

I guess that leads to another question - what is the gelatinization temp for buckwheat?
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still_stirrin
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Re: Protein Rest/Flint Corn

Post by still_stirrin »

Bee wrote: Fri Dec 31, 2021 6:53 am I guess that leads to another question - what is the gelatinization temp for buckwheat?
60*C to 80*C (140*F to 176*F).

But, it would be much easier to malt. It will malt much like barley and that will break the carbohydrate chains to convertible starch. And it will give you a richer flavor from the grain too. Definitely worth the time and effort.
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Re: Protein Rest/Flint Corn

Post by Oatmeal »

still_stirrin wrote: Fri Dec 31, 2021 6:50 am Yes, barley (or buckwheat) husks will leach tannins at corn gelatinization temperatures. So, the amount of tannins will depend on the percentage of the grainbill that the wheat or barley is … keep it low and the tannins can be dealt with during cuts.
The implication here being that the tannins come over in a specific fraction, and can be cut?
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