Millet Mash - Infusion vs steps

[billl]

I've been trying to work on a millet mash schedule following the multi-step approach outlined in other threads. The extraction rate has been right in line with Barley at about 36 point. Unfortunately, the attenuation has been horrible. I decided to devote today to a test batch and take measurements at every step.

I mashed 2.75 lbs millet in 1.5 gallons of water for a 2.18 ratio. Temps were raised in each step using the "Direct heat and stir like crazy" method. For the conversion step, I used 150 degrees. No additional enzymes were added. I stirred every 10 minutes and took gravity measurements and did starch tests. At 1 hour, starch tested negative. Gravity equated to 27 points per lb.

Based on my barley mashes, I'm usually around 90% converted at that point, so that would put a maximum points at 30. That seems to be in line with what others are reporting for single infusion mashes with a 2 hr rest.

From there, I raised the temp to 180 degrees and held for 10 minutes to assure I had complete gelatization. After cooling back to 150, I took gravity and starch measurements. The gravity had jumped to the equivalent of 36.5 points and starch tested positive. Clearly, there was a LOT of starch still available. Since I had fried my enzymes at that temp, I added the diatase from kraus along with some generic alpha amylase from the local brew shop. I continued to test gravity and starch for the next 2 hours. The gravity held constant and the starch test went from jet black, to a gray/black. Some additional conversion was taking place, but there was still starch in solution after a 60 minutes initial mash and a 120 additional mash! No wonder I was always having attenuation problems.

So, I think the takeaway is that I'm going to give up on the complicated schedule. That method extracts significantly more starch, but it takes forever and seems to require additional enzymes in the mash and likely in the fermenter to deal with the remaining starch. I'd rather just buy additional grain and accept the lower efficiency. I might have a different opinion if I was trying to make a living at this, but I'm only making small batches for friends.

 

[hipturn]

Thank you!

 

[glutarded-chris]

@ billl - when you say your attenuation has been horrible do you mean it finishes too low or too high?

My first AG batch finished at 1.006 which is the lowest I have seen by far. Igliashon talked about switching to a single infusion and getting better attenuation: Post #5 of https://www.homebrewtalk.com/f164/would-perhaps-work-millet-mash-517361/#post6724721
I think my next AG batch I am going to try a 30 minute protein rest at 123F with the diatase enzyme addition and then go to 155F for a two hour starch rest and then 2 or 3 sparge steps to rinse the grain well. The protein rest is what the enzyme manufacturer recommends and the long starch rest seems to be what Igliashon and Osedax have used with success. I figure with such a long second rest, I will just get the mash to 160F and it won't drop below 150F in my insulated mash tuns.

 

[billl]

My FG has been WAY too high. It looks like the starches getting released after the decoction/boil step are not fully converting.

Not sure about the synthetic beta amylase, but in barley, it denatures in about 40 minutes in the 140's and very rapidly at 155. I think the main benefit if that long alpha rest is that you get some additional gelatinization happening while the naturally occurring Alpha is still active.

Also, I should note that I made no attempt to save some of the naturally occuring enzymes by reserving some of the clear wort. I was mostly interested in the yield, not fermentability for this test, and messing the volumes would have just made the calculations more complicated.

 

[Osedax]

This is some good stuff. Glad to see this type of experiment. What brand of millet did you use?

I usually have attenuation problems with my dark beers. I don't think it is the pH but, rather all the extra dextrins from the specialty malts combined with what you were seeing. Did you end up fermenting the worts?

 

[brwmistr]

Good to see this type of experimenting. I did a small test with 1 gallon on Saturday to see if I needed the acid in my water. (my local water report doesn't have the tests done for what we brewers need without $250 investment added to the test). It turns out that without the acid in the water to drop the pH to 6.0 to start the natural Millet enzymes don't convert the starch well enough. I only used pale home malted millet and it turned into a white somewhat sweet wort that I wouldn't want to serve. I don't get this when my water has a start pH of 6.0 and I use my darker malts. But then I also use an profile let 40Cel rest then 55Cel then I remove the clear liquid enzyme and reaise the wort to 70cel for 25min then to gel stage at 85cel. Once this is done then I drop it to 65cel add the liquid back in and hold for 90min. This has been a long 8 hrs process for 5 gallons but it's constant and makes good beer so to me that's what I'm going for. When you do a single infusion mash how does it look when your done fermenting it? post a pic if you get the time.

 

[igliashon]

For what it's worth, I cannot represent billl's results. I mash out and sparge hot (180 degrees) every time and my runnings never test positive for starch. However, there was one time I did a batch sparge with 195 degree water (HLT water dropped below temp probe so the heater stayed on and overheated the hot liquor), and that turned the mash into porridge. No amount of enzymes or waiting thinned it out and I ended up having to scoop out half the mash by hand to add enough water to thin it out to where it would run again.

I do have attenuation problems when using large proportions of specialty malts--my stouts ALWAYS stall around 1.018-1.020 until I add more amylase to the fermenters. My wit however will go down all the way to 1.008 without any intervention. So there's definitely something going on that I haven't figured out yet, perhaps a pH issue. Perhaps that is why some people also have such a struggle with millet? I'd love to see some experimentation to optimize mash pH.

 

[glutarded-chris]

@brwmistr - Ward labs will test your water for far less than $250. Not saying that I have a great handle on water chemistry, but I use the Ward lab test and then a spreadsheet calculator from John Palmer to calculate salt additions for the style. I brew pale ales and light amber, so I just use the same water profile. Made sure there was sufficient calcium, put the RA low and balanced the chloride and sulfide. I don't add acid to bring the water pH down before adding to the mash. I tested the mash temperature during several mashes and the mash pH was maybe a little high, but still in the range so I just keep using the same profile.

+1 on liking all the testing going on and I hope to contribute at some point, but I don't really see how to make sense of it all. I have never passed a starch test, ever! My partial mash batches all finish around 1.013 and my only all grain, which did not pass the starch test went to 1.006 (no amylase in the fermenter).

 

[Osedax]

As an FYI, millet is an alkaline grain. Barley is considered an acidic grain. It is highly advisable to add some level of acid to the mash or even the boil of lighter beers. It helps both efficiency and taste. This is true even for barley brewers.

I monitor my mash pH and have played around with it. I try to keep it between 5.4 and 5.6. I haven't seen it effect attenuation but, it has helped efficiency slightly. Depends on your water though.

 

[brwmistr]

@brwmistr - Ward labs will test your water for far less than $250. Not saying that I have a great handle on water chemistry, but I use the Ward lab test and then a spreadsheet calculator from John Palmer to calculate salt additions for the style. I brew pale ales and light amber, so I just use the same water profile. Made sure there was sufficient calcium, put the RA low and balanced the chloride and sulfide. I don't add acid to bring the water pH down before adding to the mash. I tested the mash temperature during several mashes and the mash pH was maybe a little high, but still in the range so I just keep using the same profile.

+1 on liking all the testing going on and I hope to contribute at some point, but I don't really see how to make sense of it all. I have never passed a starch test, ever! My partial mash batches all finish around 1.013 and my only all grain, which did not pass the starch test went to 1.006 (no amylase in the fermenter).

I live in Canada so to send a water sample to the USA to be tested is a bit much for me. But the info is much appreciated. I have been doing lots of reading about millet but have never come across a quote from someone to say Millet is alkaline. That's very interesting and would make sense why adding the acid to my water makes my efficiency at 77%. I havn't even thought that a starch could be acid based or alkaline in nature...Ummmm!

 

[brwmistr]

I found an article talking about Millet being Alkaline grain. First article I've read that suggested such a thing. I add citric acid to lower the pH to 6.0 from 8.0 and add 1/8 sodium metabisulfate into 5 Gallons of water. Doing this gives me very clear beer and I don't even test for starch any more. My first batch I didn't add acid and had a very white beer that smelled like beer and tasted sort of like beer but looked like rice water. I don't get that any more since I step mash but I will give single infusion a go here soon just to see if I can drop 4hrs off my time. That would be great .