I recently got a 50 lb bag of wheat from John, with the idea to experiment making my own malt for use in homebrewing beer.
The short version of how this works is that you get the grain to begin sprouting, during which it produces enzymes that make the stored energy in the seeds available to the growing plant. Basically sprouting converts the starch to sugar. Once the full amount of enzymes is produced, but before the growing seedling has had a chance to consume much of that stored energy, you stop the process by dehydrating the seeds under moderate heat (too hot and the enzymes break down). When you're ready to brew, you'll set up conditions for the enzymes to convert the starch into sugar for the brewing yeast to consume.
The long version of how it works can be found in a few places online. I referred mainly to this page
Most of what I found online is specific to malting barley, but I found a few references to differences in approach when you're dealing with wheat (mainly, wheat sprouts quicker, and there is an extra step with malted barley - a higher temperature kilning after it's dried).
I started with a fairly small batch of grain for my initial trial, about 2.5 kg.
Step One - Soaking
The first thing you want to do is to soak the grain for a 6-8 hours, then drain it and let it breathe for about as long, and then soak it again. As I was working around other things in my life, like work and sleep, I ended up soaking for about 8 hours, letting it breathe for about 9, then soaking for 5.
I use a lot of 20L food-grade plastic pails in brewing, and I have one that I've fitted a spigot to for sparging grain with. I grabbed an extra pail, drilled a few dozen small holes in the bottom, and put it inside the pail with a spigot - this gave me a nice container for soaking the grain, that was easy to drain.
When I initially filled the pail with water and stirred the grain up, there was practically no chaff - the grain seems very clean. I had thought I might have to pour out that first batch of water to get rid of chaff, and soak in a fresh batch, but I just left the first batch.
Step Two - Sprouting
The next step is to keep the grains evenly moise, and let them sprout until they are what's known as 'fully converted' - at this stage, the acrospire (the beginning sprout that will turn into a stalk of grass) is about 3/4 the length of the seed in most of the grains. When malting barley, the acrospire is inside the hull, so you have to cut open a sample of seeds to see how it's progressing, but wheat has no hull, so you can just grab a handful of grain and look.
The goal is to get even conversion - you don't want too many of your grains to be underconverted (less than the full enzyme production) or overconverted (much of the starch used up). So, you want to stir the grains as regularly as you can manage, to keep the temperature and
humidity that the grains are exposed to consistent. I managed about twice a day.
By 24 hours after the final soak, most of the grains had a little
white bulge at one end, where the acrospire and roots were beginning to form.
By 36 hours, most of the grains had visible rootlets 1/4 or more the length of the grains.
At 72 hours, there were acrospires on most of the grains. I figure about 90% had at least some acrospire, with maybe 2/3 of those (so, 60% of the total) in the neighbourhood of 2/3 the length of the grain. The grain also felt like it might be drying out a bit, so I rinsed it briefly with fresh water - letting it soak just about 10 minutes before draining it again.
Step Three - Drying
At 96 hours or so after the end of the soak, I decided it was time to stop the sprouting.
I weighed the grain at this point, and it was around 3.75 kilos, about 1.5 times the starting weight.
I spread the grain out on cookie sheets and baking trays, and put them in the oven. It turns out to be a good thing I only sprouted this small batch of grain for my initial test - it completely filled my
At its lowest setting, my oven seems to swing between about 55 and 70 C - too hot for drying grain; the enzymes would be broken down (it might be useful for making crystal malt, but that's another experiment for another time). I settled on turning on the oven light and putting a couple of little 25 W reading lamps in the oven. This produced a steady temperature around 40 C, which is about right for this purpose.
The drying took around 2 1/2 days. Ideally you want lots of air circulation, which my oven does not provide; if I had a food dehydrator, or one of those ovens with a convection fan, it probably
would have gone faster. Next time around, I probably will see if I can borrow a dehydrator from a friend - as I keep going with this, I'll want an approach that dries the grain down quicker, and doesn't put the oven out of commission for days on end.
After drying was complete, the grain weighed around 2.2 kg, around 90% of its starting weight (that's including a bit of a fudge factor for the wheat I kept eating throughout the process to see how its taste and texture were changing).
You want to avoid brewing with grains that have the rootlets still on they apparently contain quite a bit of protein, which can cause your beer to be very cloudy, without contributing anything much to the taste. I put the grains in a sieve, a handful at a time, and rubbed them to sift out most of the rootlets. Even with this small amount of grain it was a pretty tedious process - next time, I will try using an old window screen for this part.
|Mark...hard at work|
When dealing with barley, there's another step after drying, kilning, in which the grain is heated to a higher temperature for a few hours, to give it its desired colour and flavour. This can range from four or five hours at 70 C for a pale malt, to much higher temperatures for dark chocolate malts. From what I found online, it seems this step is not typically used for wheat malt, and I didn't do it.
Step Four - Beer
I've made a very small test batch of all-wheat beer, which I'll write about another time - maybe once it's ready to drink.
Hopefully Mark will post some results of his beer project and perhaps a picture or two. I would love to see the finished product from another use for our wheat!