Thanks for the great articles Milletman! Very informative. I'd found a few scientific papers on malting millet, but was struggling to translate them into a practical method. I particularly like your ARSE (thats "Aerodynamic Roots and Shoots Extractor" for those with filthy minds!).
I'm proud of my ARSE.
1. for the steeping air rest, is using a SS air stone to aerate the steeping water acceptable, or does the grain need to be removed entirely?
You need to change the water after about 8 hours or so anyway to as it leaches out undesireable compounds, so I just leave it dry in between. I have used a fish tank bubbler during steeping but it seemed to promote germination before the grain had finished taking up water.
2. Is there a particular reason you've settled on 25C for the steep temp? The studies I've read suggest that 30 to 35 C steeping temp yields higher diatastic power and alpha amylase. Just curious.
Anywhere between 25-30C seems to work well with millet, I have tried steeping at 35C but the germination temperature would then be hard to control and would run up to 45C. At 25C steep the germination temperature does not try to "runaway" until the last 12 hours.
The lab studiers are done with small samples in a controlled environment which is difficult to replicate. Also malting losses are higher at 35C.
3. How thick is the grain in the germinating tray? And would you recommend a tiered setup with several trays stacked on top of each other (with a decent air space between).
The germinating tray is 10cm deep. My first attempt was to build a stacked germinator/kiln but it did not work too good. I couldn't get decent airflow during kilning as the cumulative bed depth was too great. Keep it shallow and a low watt axial fan will do the job easily.
4. What did you seal the wood with (to prevent the fungal growth)?
A 2 part timber sealer that I had lying around that we used on the timber benchtops in the kitchen, can't remember the name.
5. I assume you can add the rice hulls at the beginning of the mash(never used them before). Rather than transferring the hot mash onto the rice hulls for the lauter, I'd prefer to have it all in one vessel at the same time and mash and lauter in the one mash/lauter tun.
I have tried this method and prefer to add the rice hulls at the end for a couple of reasons.
Firstly, if the rice hulls are in the mash then more mash water is required to maintain the same lt/kg ratio for workability. For a 4 kg mash I use 18 lt of mash water and 15 lt sparge. If I add the 0.8 kg rice hulls in the mash then I would end up with 21.5 lt in the mash and 11.5 lt sparge, and my mash tun would overflow.
The second reason is that I prefer to use a separate lauter, I have tried mashing and lautering in the same vessel with generally poor results and have tried many setups; HERMS, slotted copper manifold, SS false bottom. Because of the need to have a number of temperature rests and lots of stirring I always ended up with fine particles and ungelatinised malt clogging the manifold, resulting in a stuck sparge (2-4 hrs) and crappy efficiency.
My current method gives better efficiency and the sparge is 90 minutes at the most (darker beers) and as quick as 45 minutes (fly sparge). I have found this is what works best for me.
6. How important is getting the pH right? I don't bother with my current all barley malt mashes, and I turn out fairly good beers. Is it critical to the gluten free mashing process?
Enzyme levels are much lower so anything that can be done to halp them will improve the conversion - keep the calcium level up and the pH in the right range. I was probably mashing my beers at around pH 5.7 before I started checking, now I do it at 5.4 and get about 10% more efficiency, less haze and no astringency. I was making good beer before pH adjustment but now they're better.
7. How do you think a millet base wort will go with the 'no-chill' method? I assume that it will be the same as a barley based wort?
Should be fine, I've done one no-chill with a sorghum malt wort and it worked fine.
Cheers, Andrew.
