A few days ago, I decided to try my hand at malting barley. Why not jump in at the deep end? I'll go straight for a Crystal Malt. After all, Pale Malt is easy enough to obtain; it's the specialised malts that are more difficult to get hold of.
I bought a 5kg bag of Barley from the local farm-supply store, and put 1kg into a bucket, covered with water, and soaked overnight.
Mistake 1: I should have pre-screened the grain first. There was a fair quantity of undersized grains, chaff and bits of stalk. I doubt that this grain would have been allowed into the silos at Caledon, but, after all, it is being sold as bird-food, not as malting-quality Barley.
After soaking, I kept the grain moist by wetting it twice a day, just as I would do for any salad-sprouts. After 24 hours most of the grains were putting out little rootlets, and after 36 hours I could see the acrospire growing by dismantling individual grains. On average grains were about 30% converted at around 48 hours -- that is: the acrospire was about 30% of the length of the kernel.
By this morning -- 3½ days -- quite a number of the grains were "overconverted" -- thay had already started sprouting. Ideally I wanted to catch them when they were 75 to 100% converted. Actually, I probably did get close to that for the majority of the grains, and, no doubt, some are still a little under my target.
Learning 2: The vertical turning of the grain is extremely important. Happily I figured this one out quite early in the soaking, so not too much harm done. The grains at the bottom of the bucket stay wetter, but get less air; the grains at the top tend to dry out, but end-up growing more quickly. So the vertical turning is important to try and even-out the germination rate of the grain population. I think that 3 turnings a day would be optimal. More than than would only increase the risk of damaging the tender growing grains.
Now, since I want to make a Crystal Malt, then next step is to wet-roast the grain, and hold it at a saccharification rest (69 or 70°C) for (I guessed!) about 50 minutes. Essentially we want to conduct a normal mashing process -- turning starches into sugars -- but keep the sugars inside each little kernel instead of dissolving the sugars out into wort.I just plonked the malted barley into a big pot and put it on the stove at a very low heat with a bit of hot water in the bottom of the pot to keep things steamy and moist. This gave me a bit of trouble in maintaining the correct temperature. Were I to try malting on a regular basis, this is one of the steps I would bear down on to get better; I think that a steam-driven warming might be more controllable, or perhaps a simple double-boiler setup. 30 Minutes into the mashing/roasting step I could clearly (though not strongly) taste the sweetness developing, so I couldn't have missed the temperature window too badly.
Learning 3: Even using the biggest cooking-pot we have I don't think we could comfortably roast more than about 1½kg of malt at a time. One would certainly need/want to handle larger volumes than that, and even more so if I want to produce a Pale Malt.
The final step -- kilning -- was done in the oven. I spread the malt out on a couple of baking trays so that the grain-bed is not too thick, and stuck them in the oven at about 130°C -- or as close to that as the oven thermostat will manage. The grain was turned and mixed roughly every 30 minutes to try and ensure even toasting. After 30 minutes the grain bed was starting to dry out, and a delicious, honey-ish, caramel aroma started wafting through the house. At 60 minutes, there is still some moisture in the individual grains, but the kernels have developed distinctly tough skins. Rootlets have mostly dried out. 90 minutes: Grains are developing a crunchy outer coat. Some are getting distinctly chewey inside, and the roasting pans are gaining a small amount of caramelly deposit on them. I see some challenging washing-up in my future! I originally -- based on reading and thumbsuck -- planned to kiln the grain for 2 hours, but at that stage the grain still didn't get that really Crystal crunchy texture, so I kilned for an additional ½hour, and then left the trays in the oven while it cooled. Turns out to have (maybe!) been a mistake to add the extra ½hour.
After cooling, the malt is dentalwork endangeringly crunchy. Flavour is really good, tending almost to the Dark Side (burnt sugar flavour), but strongly well of Caramel. Colour: I would guess at a 60 to 80L range somewhere. 1kg of Barley resulted in 690g Crystal Malt, though I certainly lost a bit during a accident whilst rinsing the sprouts, and a bit more to tasting at every stage of the process.
I have subsequently tripped across another homebrewer's account of trying to malt barley at home. Sadly the blog lacks an account of how it turned out. That process mentions a couple of air-drying steps between soaking and mashing, and after mashing, but before roasting. I think this would probably be a good idea, and might help to reduce the kilning time.
Lessons for next time: Better temperature control at the mashing/roasting stage! And perhaps mashing for longer.
All-in-all I would call it a success, but the final test awaits: Trying it out in a brew!