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Brewing Up a Science Experiment

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igliashon

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Next week I'm going to use the extra day off to do the following brewing science experiment.

I'm gonna brew a 3-gallon batch with just 5 lbs each of sweet potatoes and (wet-toasted) sprouted quinoa as the *only* fermentables, but I'm going to split the mash as follows:
-2.5 lbs of quinoa mashed with 1/2-tsp Crosby & Baker amylase formula in one kettle
-2.5 lbs of quinoa mashed with 2.5 lbs of pureed sweet potato in the other kettle

I'm gonna crack and then cook the quinoa into goo first, to thoroughly gelatinize. I'm gonna let them both go for 2 hours after stepping up to 150°F, and then taste each and also test a sample of each with iodophor and see if there's a difference. Then I'm gonna mix 'em both together, add some rice hulls, and use my grain bag and bottling bucket as a makeshift lauter tun and sparge into the kettle. Oh, and the other 2.5 lbs of sweet potato I'm just gonna slow-roast in the oven while the mash is happening, and then puree and add before sparging.

And then I'm gonna make what will hopefully be a simple amber/copper ale out of the wort, with some Columbus and Willamette hops.

What I hope to learn from this is how sweet potatoes compare diastatically to amylase formula, and also see if I can make a tasty beer with just sweet potatoes and quinoa. Gonna be a PITA to toast and then cook all that quinoa, though.

I welcome any suggestions and criticisms RE: my experimental design here.
 

Andrew5329

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You proabaly want to add amylase into both kettles as potatoes have no diastic enzymes of their own. I don't think that the enzyme in your quinoa will be enough to fully convert the potato starch. Mixing them together after the fact wont give you conversion because at 150F your enzymes will usually denature after about 45min-1hour (normally plenty of time for full conversion in a typical mash), so the last hour of steeping doesn't accomplish a lot.

If you really want to do the experiment be prepared to add enzyme when they mix together as to allow the conversion of the potato starch to finish.
 

KevinM

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We've referenced quite a bit showing that various species of sweet potato include enough enzymatic activity to compare to barley. Usually anywhere from 100-300 Diastatic Power, hence the test. In fact, scientific studies have shown that it works just fine but don't get into some of the different aspects.

My recommendation is not to combine the two, but to keep the two batches separate with the only difference being the enzyme source.

Your control sample would be the one created using amylase formula
Your experimental sample would be created using the sweet potato.

You can then let both ferment to completion and give a qualitative comparison to the rest of us. Personally, I'd like to hear about the qualitative properties of differing amounts of sweet potato as a fermentable.
 
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igliashon

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My recommendation is not to combine the two, but to keep the two batches separate with the only difference being the enzyme source.

Your control sample would be the one created using amylase formula
Your experimental sample would be created using the sweet potato.
That would be ideal, but to do that I'm going to have to go out and buy some 1-gallon fermenters, and also double the work--two sparges, two boils, two chillings, etc. I suppose it might be worth it, though, even if the "experimental" sample doesn't turn into drinkable beer. At least then I'd know to stop wasting time trying to use sweet potatoes for enzymes.

If I do it this way, then I'll take the 2.5 lbs of oven-roasted sweet potato and add it to the control sample after mash-out but before sparging, just to make the comparison more even between the two batches (I'll still likely get equal sugars from the sweet potato this way, with the only variable being how much conversion I get from the quinoa).
 
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igliashon

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So I haven't done the above mentioned experiment yet, but since I wanted to do a trial run with the amylase, I used some for a Belgian Blonde style on some millet. I cooked 5 lbs of millet (2 of which had been sprouted and lightly toasted), and then added water to cool to about 155°F, and added two tsp of amylase formula. Three hours later I added another tsp. After four or five hours, my starch tests were still turning purple and the mash had sweetened only a tiny bit. I left it overnight wrapped in a bunch of towels and will see how it's doing this afternoon when my clinic shift is over, but so far this is not giving me a lot of reason for optimism. One thing I will note--the porridge was extremely thick before adding the amylase, but it has thinned out considerably, with the grains now being suspended in a white starchy-tasting liquid.

After reading on the Crosby and Baker site that "1 Tsp. Breaks 1,4 linkage in starch during liquefication, producing dextrin and a small amout of maltose. Leaves 1,6 links, therefore self-limiting. Use if you have a starch problem in storage, or in light beers, or in mash tub to make more", I'm concerned that I basically now have a ton of liquid maltodextrin, which isn't going to be very sweet or fermentable.

My plan is to go ahead and brew with it, add some extract sugars and whatnot and see how it turns out. I'm also gonna take about 12 oz of the strained mash liquid before adding the extracts, boil and cool it separately, take a gravity reading and ferment it out, so I can gauge how much fermentable sugar I got out of the millet. I'm gonna do this before continuing with the original experiment, because if the amylase doesn't actually get me fermentables, there's no point in comparing it with the sweet potato.
 

MariposaSouth

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Its too bad with the tests we can't differentiate between starches. Out of everything I've tried mashing so far, sweet potato starch has the highest gel temps (172F - 176F). I think you may get full conversion on your quinoa, but still have plenty of starch left from the sweet potato. Even soaking the SP's 1st (to extract the enzymes), straining and gelatinizing the sweet potato, then adding the decanted "enzyme water" back at mash temps, this could still be a problem, because your enzyme water would likely have starch molecules in it too.
I know that doesn't help, introducing problems w/ no solutions, I just can't figure it out...
 
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igliashon

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Alright, well, 24 hours later, it's a bust. Strained out the solids and had a starchy milky wort with just a tiny hint of sweetness. Still epically failing the starch test. And it tastes a little bit like an ashtray from when I scorched the millet when gelatinizing it. Guess I'll be brewing something else today! Back to the extract (for now).

Anyone got any bright ideas as to why 3 teaspoons of amylase--despite the fact that it significantly lowered the viscosity of the millet-porridge, and thus clearly did *something*--failed to yield a sweet wort? Anyone out there done a successful mash with Crosby and Baker amylase?
 

KevinM

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What was your starting amount of water during the mash? That's all I can think of process wise, though you mention a state of porridge that turns to a more liquid like state, which is really what should happen.

I'm rather expecting that the alpha amylase dextrin limit finished what it could do, and that there just wasn't enough beta amylase from the toast and gelatinization process.
...Actually, you mentioned that you cooked the millet then cooled to 150. What was your maximum temperature during this time? Did it denature the millet's enzymes?

Also.. for some reason, now that I'm re-reading... did we ever talk about the amylase enzyme and it's pretty much alpha only state, and that in previous threads we were all searching for beta-amylase for conversion?

Somehow, I think I blanked out in some of the discussion on this thread and had completely forgotten about that. I can't imagine why I even suggested trying to use the amylase mix by itself.

The things to actually try would be
1) use amylase enzyme along with sprouted millet to try to use millet's beta amylase
2) use millet's enzymes alone
3) use sweet potato's enzymes with millet.
4) cook millet, add amylase mix, let the alpha do it's thing, then add raw sweet potato to let the beta do it's thing and stop the process when you desire.
 
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igliashon

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I didn't measure the water precisely, just added enough to make a stiff mash out of about 2.5 gallons of porridge (cooked 5 lbs of millet in about 10 quarts of water, then added about two-thirds of a gallon of water; total volume was a bit over 3 gallons).
 
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igliashon

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...Actually, you mentioned that you cooked the millet then cooled to 150. What was your maximum temperature during this time? Did it denature the millet's enzymes?
Yes. I wasn't planning on getting enzymes from the millet, I just wanted to see what the Crosby & Baker enyzmes would do by themselves. And now I know!

The things to actually try would be
1) use amylase enzyme along with sprouted millet to try to use millet's beta amylase
2) use millet's enzymes alone
3) use sweet potato's enzymes with millet.
4) cook millet, add amylase mix, let the alpha do it's thing, then add raw sweet potato to let the beta do it's thing and stop the process when you desire.
I think I'm leaning toward number 4. The question I have is, how much sweet potato would I need to add to get enough enzyme to convert 5 lbs of grain? I've got 5 lbs of toasted buckwheat and I'd like to try mashing it with the alpha and then adding sweet potato, but my kettle's only 5 gallons and it was practically full when I did the 5 lbs of millet.

I'm thinking maybe I could even do a decoction mash sort of: puree the sweet potato, put it in a grain bag, soak it for an hour in the strike water heated to strike temp, remove, squeeze bag, then dump the sweet potato into kettle #2, add a little more water and cook to gelatinize. Then add back to the first kettle, along with the pre-cooked buckwheat and the alpha amylase formula, get the temp to around 153°F, hold for a couple hours and see what happens.

The other question I have is, don't the people who make chestnut beer do it by adding just the Crosby and Baker amylase formula? If so, it seems to work fine for them...if not, what are they using and where do I get it??
 

KevinM

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If we take the low end of 100DP, then a theroretical minimum of 35DP average gives you needing 3 pounds of sweet potato per 5 pounds of 0dp grain. (300/8=37.5 DP average).

Though I've seen recommendations not to go below 65 DP, which would mean 10 pounds sweet potato. (1000/15=66.6 DP average)

Personally, I'd do what you mentioned, maybe a step further using malted grains. my earlier plan with my malted sorghum was supposed to be
crush grain, puree sweet potato
steep/rehydrate to extract as much enzyme as possible @ 2qt/pound, then I questioned about doing the protein rest before or after gelatinizing.
gelatinize
my first test was going to be only gelatinizing the sorghum. The second test would gelatinize both.
I had some processes that I wrote down and wasn't going to talk about until I tested them, but I developed a problem with my germinator and have been waiting until I had enough money to replace the humidifier portion.
 
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igliashon

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Dang, I don't think I can do 15 lbs of grain in my BIAB system. Maybe if I cut it down to a 1-gallon batch, with ~1.67 lbs of buckwheat plus ~3.3 lbs of sweet potato? I guess for an experiment like this, that's more sensible anyway. No sense wasting all that buckwheat if this doesn't go according to plan. One worry, though, is that the flavor from the sweet potato might overwhelm the grains. I guess it's still worth a shot, though...if it works, *then* I'll worry about scaling up.
 

KevinM

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It is a lot of sweet potato. One thing as well is that there may be a loss of enzymes when taking the grain/sweet potato out of the initial strike water. Even if we assume a complete eqlibrium of enzymes, we're removing about half the enzyme and denaturing it during the gelatinization process.
Even if we ground both grain and sweet potato to the finiest texture possible, I think that some of it will still be locked up within cell walls, so I'm expecting some sort of loss in this process. This is why I'm not sure about using the current numerical minimum.
 
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igliashon

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Hmm. Maybe I should wait to try this until I've got some malted buckwheat to play with.
 
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