I'm Gluten-Free and recently started brewing. I've been mooching off this forum, and now that I've got a few successful sweet-potato brews under my belt (thanks to you), I'd like to chime in. Note - I'm still building up my knowledge and equipment as I go, so the below is eyeballed rather than exact - but it's worked well so far.
I'm combining 2# buckwheat and 6 sweet potatos, a blender and a strainer. Note: the blender creates a really fine mash, so my current brews do require a bit of leg work to separate wert from mash (hence the strainer). I'll finder better ways & equipment with time.
Sweet potato prep: scrub the potatos but leave skin on. Chop small enough for blender to handle. Blend with hot water, set aside for mashing.
Buckwheat prep (two options)-
Option 1: malt, dry, roast, then crack with grinder, then add to sweet potato mash with more hot water.
Option 2: is a huge time saver - malt, (skip drying / roasting), blend with hot water directly, then add to sweet potato mash.
Mashing: let stand on low heat for an hour. Strain and collect liquid wert in a large pot. Add more hot water to sparge and strain (repeat until strained liquid runs more or less clear). As a last round, add water to the mash and boil for 30 minutes. Strain and cool this off before adding to the already collected liquid.
Boil: Then Very slowly rais the temperature of the wert (this probably continues some enzyme action for another 30-40 minutes). When its eventually at a boil, I added about 2 cups of raw sugar and my 1st bag of hops. After 40 minutes, + 2nd bag of hops. After 10 minutes + 3rd bag of hops. After ±3 minutes, remove all the hops bags. Cool the Wert as quick as possible.
Fermentation: 20 days in the bucket, 1 week in the bottle. I have only just aquired a hydrometer and thermometer, so I'll have more details in the future. I'm in the process of making more beer now.
Flavor / color: I have been gluten free for a while, so maybe my standards are low, but I really enjoyed my beers. The rate that my finacé consumes it indicates that they might actually be ok for a normal pallet too. Roasting the buckwheat gives a darker color (see photo with the pour, vs. photo of the 2 clear bottles in the fridge). Roasting also produces a change in the flavor, but I can't say which is better - thats up to personal preference.