Unmalted millet and sweet potato experiment

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simon12
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Unmalted millet and sweet potato experiment

Post by simon12 » Thu Mar 05, 2015 2:38 am

This was an experiment to see if sweet potato can be used to convert starches in millet to fermentable sugars it was alot less scientific than I had hoped and is the grounds for further experimentation. So here is what I did.

Ground 300g of bird food grade white millet in a blender, tried to blend 3 x sweet potatoes (380g) didn't work and went everywhere so grated the remainder (very roughly 300g). Boiled the millet only in a minimal amount of water for 15mins when it cooled below 70c (with hind site I have no idea why) added the sweet potato and stirred in then added boiling water to bring the temp to 68C total volume now around 4l. Held temp for 1 hour (it dropped to 63C over the hour) strain through and sieve and measured gravity which was 1.030 and just over 2l of liquid so something definitely happened and I don't think thats to bad with no sparge. It is seriously cloudy and does not look like anything you would want to drink loads of particles in it as I could not filter it except through a sieve. I planed to leave it there but decided to do a boil and check it ferments. Boiled for 1 hour adding 6 hop pellets at the beginning, had to add 500ml part way through as it was drying out end result 1.3l sg 1.046. Added a sprinkle of gervin GV12 now in demijon waiting to see what happens.

My thoughts so far, no idea if the sugars (assuming they are there) came from the starch in the millet (what I am hoping), starch in the potato (should not convert as it should need a higher temp which would denature the enzymes) or just sugar thats naturally in the potatos. I am not going to be able to make anything thats going to produce a drinkable end product unless I do much larger batch so I can drain it off the huge the sludge that would hopefully drop out in the boil or later in fermentation and be partly filtered out in the sparge. Based on rough estimates if the efficiency increased but half by doing a full sized (23l) batch 1kg of millet + 1Kg of sweet potato should produce more sugar then 1kg maris otter.

Is my thinking on this in anyway flawed (except that its all very approximate)? Any idea what its worth trying next between:
A similar experiment with just the potatos for comparison
A full sized batch of the same millet potato mix to see if its worth drinking anyway
Hold the potatos at 65C for half an hour drain out the potatos add the millet and mash for another hour at 65C hoping to extract the enzymes for the potato to convert the millet in a similar experiment hopfully doubling the quantity.
Any other suggestions?

Apologies if this is poorly written its my 1st go writing something like this since school 20 years ago. Note I am wanting to make a millet based beer not a potato beer they are just there for the enzymes.

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Re: Unmalted millet and sweet potato experiment

Post by basswulf » Thu Mar 05, 2015 9:10 am

I've no idea about what result you'll get but let us know when you take a sip. I'd let this one ferment out and, if you've got enough, even bottle it and let that sit for a few weeks before getting going on the next batch - observe it through the full process. At that point though, it would be ideal to run several experiments in parallel for the next lot.

I'd be hesitant about making 23l unless you are sure it will turn out well. Much smaller quantities will still yield enough to bottle small amounts (and use smaller bottles too), making it possible to compare two or three approaches at once.

Wulf

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Re: Unmalted millet and sweet potato experiment

Post by oldbloke » Thu Mar 05, 2015 10:19 am

The big problem I have with this is that with "normal" beer, a good deal of the flavour is due to the roasting of the malted barley. You don't have that, you just have a source of sugar, so it's hard to guess what the flavour may be. It should be fun finding out though!

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Re: Unmalted millet and sweet potato experiment

Post by simon12 » Thu Mar 05, 2015 4:31 pm

Thanks for the replies. The problem with the small batches is I cant filter out the huge amounts of sediment (its so much finer than barley) and even when it settles there is not enough of it to syphon it off. The 1.3l in a demijon has now settled about half into a light brown/grey sludge at the bottom with a cloudy yellow brown liquid at the top, if I made a full size batch i could lose alot of this filtered in the sparge and leave the rest in the boiler. There is no way I can bottle anything from the 1.3l made yesterday if there was 3 times more I could maybe syphon of a few bottles from the top. I will put a bit in the oven on the lowest setting and see what it looks like. Anyway I got some richies amylase delivered today so am going to see if that alone converts the millet or not will post back shortly.

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Re: Unmalted millet and sweet potato experiment

Post by basswulf » Thu Mar 05, 2015 5:42 pm

You could try a pinch of Irish moss in the boil; a highly flocculant yeast might also help. Anyway, cloudy doesn't mean undrinkable - think of the classic wheat beer which isn't expected to be as clear as a typical barley based brew.

Wulf

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Re: Unmalted millet and sweet potato experiment

Post by simon12 » Thu Mar 05, 2015 6:23 pm

I did actually add a bit of irish moss but I have to tip it out anyway so it made little to no difference. Its not just cloudy is more porridgey which I think is how they drink it in Africa. Anyway the next experiment will be mashed in 10 mins so will have a gravity reading soon (also remembered this time to check the gravity before which read 1). Also the grain being raosted has been in for an hour and a half temp started at 50C slowly raised to 100C and looks no different to how it started go going to 125C.

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Re: Unmalted millet and sweet potato experiment

Post by simon12 » Thu Mar 05, 2015 7:07 pm

OK used 750g millet and added water to total volume 4l started to cook and it was far to thick so chucked just under half and topped up with water. mashed for an hour starting at 69C dropping to 61C with half a tsp richies amylase. ended up with 2.3l sg 1.033 so this works to. In an effort to get something to try at the end I will repeat this with 350g millet and add it to this lot leave to settle in the hope I can syphon something off alot clearer to do a boil. 1 think I noticed without the potato it does smell similar to barley definitely not the same but similar. The roasting grain has been at 130C for a bit and is starting to look slightly darker but it could be due to moisture loss so trying at 150C for a bit.

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Re: Unmalted millet and sweet potato experiment

Post by simon12 » Fri Mar 06, 2015 12:54 am

Next experiment exactly (according to budget kitchen scales 350g millet toped up to 4l water cooked cooled to 69C added amylase left for 1 hour tested gravity very low (didn't even bother recording) put back raised temp into 60s and more amylase added. Then remembered I didn't temp correct the reading so took off tested gravity was 1.024 but got 3.1L so to much water this time. Any way this is the first time I weighed and measured everything accurately enough to do a comparison. If I put this recipe scaled x10 into beer smith but use maris otter my estimated gravity is 1.028 and thats with my normal batch sparge so even getting 1.024 with this is 67% efficiency with no sparge. I am now considering this a success in terms of being able to convert unmallted millet into fermenables, I added it to yesterdays result added a crushed campden tablet to stop bacteria getting in and will let it settle, syphon the top bit off for a boil tomorrow. Whether this will taste anything like beer remains to be seen wish me luck.

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Re: Unmalted millet and sweet potato experiment

Post by oldbloke » Fri Mar 06, 2015 8:22 am

Malted and roasted, millet tastes very much like barley. Unmalted, no idea.

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Re: Unmalted millet and sweet potato experiment

Post by simon12 » Mon Mar 09, 2015 1:06 pm

Its not going well though is looking good for it working. Anyway the demijohn settled so the top half was clearish (only really compared to the bottom) boiled around 2.5L and got 1.5L sg 1.038 spilt 700ml so replaced with honey and water sg 1.052 to get enough to ferment. I tiped away the 1st lot as I had no spare demijons and is was clearly to full of sediment to ever be drinkable but it smelt exactly like a barley beer when tiped it out. I now wish I had just done a 10-15L batch in the 1st place as it would have taken less time and I have 20Kg of the stuff that only cost £1 per Kg. Now I am fermenting 1.5L of a millet beer/mead combination. Going forward I plan to try malting some and try a 10-15L batch of unmalted anyone have any perferance if I use the sweet potato or not?

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Re: Unmalted millet and sweet potato experiment

Post by vacant » Mon Mar 09, 2015 1:25 pm

I see your experiments are inspired by African millet beer. I reckon they ferment that for the effect rather than the taste. :(
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Re: Unmalted millet and sweet potato experiment

Post by simon12 » Mon Mar 30, 2015 12:25 pm

Bottled 2 bottles, almost no colour tastes alot of honey as you would expect but there is definitely a grainy beer taste behind it. I have not had time yet to do a larger batch but from the taste on this I think it is well worth trying.

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Re: Unmalted millet and sweet potato experiment

Post by simon12 » Mon May 11, 2015 6:36 pm

I nearly forgot about these 2 bottles until earlier today and the results are surprising. Its the colour of a very pale cider/perry and both smells and tastes amazingly like carlsberg with a hint of honey. While writing I think I must go to the shop down the road and get a can of carlsberg to compare.

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Re: Unmalted millet and sweet potato experiment

Post by simon12 » Mon May 11, 2015 6:51 pm

Ok its not Carlsberg or even that close but there is a flavour in there thats similar. If I didn't know what it was made from I would definitely think it was a generic lager though rather than millet and honey. Its very thin but most certainly a beer and needs further experimenting.

Chuck

Re: Unmalted millet and sweet potato experiment

Post by Chuck » Mon May 11, 2015 9:09 pm

Interesting. Any chance you could give a quick summary for the recipe for this as it's quite hard to follow split over several posts. Would be very keen to try this as I've heard lots of good things about millet.
Thanks.

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