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Old 03-26-2014, 06:49 PM   #1
igliashon
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Question Dialing in the Millet Mash

Due to the fact that my last several beers have severely over-attenuated and come out lacking good malt flavor, I've decided to go back to the drawing board and try to dial my mash in more scientifically. This is also to figure out what mashing process is optimal so that we can avoid adding unnecessary features to the brewhouse at Ghostfish.

I'm planning a bunch of small-scale trials and have already done three 0.5-gallon-size mashes, and I already have gotten some puzzling results.

Initially I am trying to definitively rule out the possibility of a single-infusion mash. I did two trials using about 12.37 oz of pale millet malt from Grouse in 0.53 gallons of water. Both were mashed at 160°F for 60 minutes on the stove, with frequent re-application of heat to keep the temps up. The only difference between the two was Trial 1 had no additional enzymes added, whereas Trial 2 had 1/8 tsp of EC Kraus Diatase added at the start of the mash. Water was RO with no modifications. After the mash, a 5-minute mash-out at 175°F was conducted, and the grains were strained out using a fine-mesh BIAB bag.

Here's the first point where I'm confused: after I mashed, strained, cooled, and labelled the worts, I checked the SG, tasted them, evaluated the appearance. Both trials went super-dark black when I first added 1/8 tsp of Iodophor, but rapidly lightened to a pale pink color (over the course of 60 seconds or so). What's up with THAT? How do I tell if that's a weak pass or a major fail of the starch test? Do I go by the initial color, or what it finally settled out to be?

Here's the second point where I'm confused: Trial 1 tasted starchy and did not clarify well during the mash at all. Trial 2 tasted very sweet and during the mash a nice clear wort collected on top as the solids settled out. HOWEVER, the SG of Trial 1 was 1.044 at 65°F, while the SG of Trial 2 was 1.033 at 65°F. WHAT is going on there? I've scoured everywhere for an explanation of how SG changes during a mash as starches convert, and come up empty-handed.

To add another data point, I did a 3rd trial, which used the same grain and water volume, the same enzyme amount as Trial 2, but split the mash into two steps: 30 minutes at 150, 30 minutes at 163 (the reported gel temp of the malt, according to the maltstress). This produced nearly identical results to Trial 1, more or less, with a slight difference in appearance and an SG of 1.042. Taste was also starchy and a little thin.

It seems like trial 2 had the best conversion, by why is the SG 10 points lower? Why are the starch tests identical, despite the obvious differences in flavor and gravity? Just to make sure it's not the iodophor, I did some "control" starch tests using sugar-water (solution did not change color), dry rice extract dissolved in water (solution did not change color) and rice flour dissolved in water (solution turned blue-black instantly).

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Old 03-26-2014, 10:19 PM   #2
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On my partial mashes, the starch tests always showed black no matter how long I left the rests. I figured I was either doing the starch test wrong or the fact that I use a little buckwheat in every mash somehow left starch no matter what.

The gravity reading cannot distinguish between starch and sugar, right. The gravity reading only tells the difference in density so maybe your results make sense. You get a bunch of starch in the wart and the gravity goes up, you convert some and the gravity goes down a bit but the sugar content is much better. Maybe we just have trouble converting a high enough percentage of starches and we always fail the simple starch test. Attenuation is probably the better indicator of how much sugar is actually in the wart.

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Old 03-27-2014, 01:35 AM   #3
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If no one knows how conversion amount affects hydrometer readings, my next test will be just straight gelatinize some malt in solution at temperature above saccharification, collect the starchy wort, split it in half, and add enzymes to one half, and then chill both to the same temperature and see if the gravities differ.

What I really need to figure out is a way to conduct several simultaneous small mashes in a manner that allows for good temperature stability. Maybe in the oven?

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Old 03-27-2014, 10:19 AM   #4
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Do you use a pH meter to monitor your test mash?

Palmer and others talk about the importance of mash pH and controlling water chemistry for good beer. I was considering getting a meter but they are pricey and a PITA to use and maintain. Since all of the literature out there is on barley mash, I wasn't really sure that the extra cost and pain would add that much value. I don't really know what I should be controlling to. For your brewery, you will probably be using a pH meter so you may have access to equipment that most of us don't. I for one, would be really interested in your results.

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Old 03-27-2014, 10:37 AM   #5
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Millet has extremely low diastatic power, iirc. Batch 1 didn't convert, therefore the SG is meaningless on batch 1. Who takes gravity readings in the middle of a mash? No one. There's no purpose in correlating that number to anything.

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Old 03-28-2014, 07:06 PM   #6
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Nothing in these trials is meaningless. If unconverted starch pushes up the SG compared to wort that has achieved close to full conversion, then that tells me something important, namely that I can gauge conversion roughly by SG. Most people don't take SG in the middle of a mash because most people are not trying to do what I'm trying to do (optimize a mash process for a grain that has no established convention to follow). I cannot afford to leave any avenue unexplored or any variable uncontrolled here.

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Old 03-29-2014, 03:10 PM   #7
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A hydrometer measures the relative density of a liquid in comparison to water. As brewers, we use a saccharometer which measures the amount of sugar in solution. Starch is mostly insoluble. If you had no conversion, your hydrometer would sit fairly low. Did you double check your readings with a refractometer?

I'm not a huge fan of chemical conversion tests. I like the ol' "if it tastes starchy then it is" test. Honestly, we don't have enough data. Both of these tests could be outliers. At that small of a scale, small variations in process could have drastic results. I would also include pH. Your best bet is to conduct this same test many more times to reduce error. Plot and graph results then take an average. Scientific method is your friend.

You could also include things like varying the time of mash and pH conditions. I might also do a mash of 163F to 150F. Gelatanization to conversion. Man I wish I could personally be there to give you a hand. This is the kinda thing I can sink my teeth into.

This is some good stuff. We just need more data. It could really help everyone with their chronic low efficiency. Keep up the good work!

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Old 03-30-2014, 06:34 AM   #8
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Quote:
Originally Posted by Osedax View Post
A hydrometer measures the relative density of a liquid in comparison to water. As brewers, we use a saccharometer which measures the amount of sugar in solution. Starch is mostly insoluble. If you had no conversion, your hydrometer would sit fairly low. Did you double check your readings with a refractometer?
Guess I should get a refractometer. But I did check and re-check each batch of wort multiple times to confirm that it was not just me misreading the damn thing.

I know starch is insoluble, but what about dextrins? I'm entirely sure I didn't simply get *no* conversion, because there was some sweetness to all the samples.

Quote:
I'm not a huge fan of chemical conversion tests. I like the ol' "if it tastes starchy then it is" test.
Sure, but what if it doesn't taste starchy?


Quote:
Honestly, we don't have enough data. Both of these tests could be outliers. At that small of a scale, small variations in process could have drastic results. I would also include pH. Your best bet is to conduct this same test many more times to reduce error. Plot and graph results then take an average. Scientific method is your friend.
Yes, I'm well aware of this. I know heat loss and vessel size are two other variables here that were not adequately controlled; the next test is going to be done in vessels of nearly identical size, and held in a warm oven to prevent heat loss.

Quote:
You could also include things like varying the time of mash and pH conditions.
Yeah, I'm getting there. First I want to optimize temperature, and then start tweaking these other variables. Mineral content, mash thickness, grind fineness, time length, enzyme quantity, etc. etc. are all factors. I only wish I had an actual lab with better equipment to control and measure things.

Quote:
I might also do a mash of 163F to 150F. Gelatanization to conversion. Man I wish I could personally be there to give you a hand. This is the kinda thing I can sink my teeth into.
Well, if you want to run some trials yourself that would be just as useful as you helping me out here!

Quote:
This is some good stuff. We just need more data. It could really help everyone with their chronic low efficiency. Keep up the good work!
In point of fact, I have at least established a mash process that yields very high efficiency and attenuation; the problem is that the attenuation is excessive and the malt flavor is lost, and the mash is very complicated. I'm trying to start from scratch to find something that is simpler and yields good extraction but less extreme attenuation and better malt flavor.

It's going to be a long journey, because once I figure it out with all pale malt, I'll start adding roast malts and that's gonna throw the whole thing off.

Things were so much simpler when I was just steeping roasted grains and adding syrups and extracts, lol. So far I've yet to produce an all-grain stout or IPA as balanced and drinkable as old mostly-extract recipes. Blondes, belgians, wits, and browns, though...those have been better than anything I could accomplish with extract.
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Old 03-30-2014, 02:46 PM   #9
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I certanly dont have the answers to your questions, but I wonder if the results you are seeing could be due to the enzyme product you used?

The diatase contains both a-amylase and glucoamylase... what if the a-amylase in your bottle is not working well, so those long chain starches in your wort are not bieng cleaved up into dextrines...but the glucoamylase is working fine, so any dextrines already in your wort are bieng converted to sugar.
This sort of scenario might explain how the enzyme spiked batch could be sweet, but also low gravity and fail the starch test.

furthur experiments with these 2 enzymes used seperately might help to pinpoint weather this is the problem. I have ordered powdered a-amylase and glucoamylase (seperately, not mixed) from brewhaus.com.

I am not sure this explains your results, just a thought.

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Old 03-30-2014, 04:19 PM   #10
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Theorhetically, mash temperatures only effect the enzymatic processes, not the grains. If the grains are already malted, we need only focus on extracting and converting those starches. If you add alpha amylase, but take it out of its optimal range, what is the point? At 160, you are at the very end of the alpha range, very close to beta. I know that Grouse recommends 163, but this doesn't really make sense to me for this reason. If you are going to use enzymes, why not try them in a normal mash schedule? Or have you already done this? Or maybe I am wrong on this?


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