I mostly lurk here but I did an experiment earlier this year to try to ferment sunchokes into alcohol. I figured I'd take the time to share the results here since there's very little info on the Internet about brewing with sunchokes.
The main challenge was to figure out how to turn fructans (complex carbs) like inulin (the main, or at least of the main carbs in sunchoke tubers) into fermentable, simple carbs. I learned this can be done with a process called hydrolysis, essentially boiling the tubers for a long time to break the complex carbs into simple ones.
Agave is high in fructans, specifically inulin, and is used to make tequila. So I used that as a guide for brewing with sunchokes and found a study about how to best hydrolysize inulin.
Link to inulin hydrolysis study:
https://www.sciencedirect.com/science/article/abs/pii/S0308814607010345
Process I came up with to brew with sunchokes:
- Harvest and give initial rinse in yard with hose
- Clean off last bit of dirt in kitchen, chop
- Boil low temp lid on. Mash it up after an hour, leave it to simmer with lid on for a while (maybe an hour or two) and let it slowly cool down over a few more hours to cook the carbs a bit more while it cools.
- The long and slow method converts as much inulin and starch into fructose and sucrose, which are fermentable sugars. Add any spices, herbs, or juice you want for flavoring. I didn't use any flavoring since this was just a chemistry experiment. At this point the boiled sunchoke water smelt sweet and almost like popcorn.
- When it's near room temp, the solids should have floated to the top. Strain or use the spigot to pour off the liquid into fermenter and compost the leftover solids.
- Add a yeast starter to the sugary water. I just used some pieces of dried fruit.
- Let it ferment for a week or two. Mine took a couple days to really start fermenting, then it got stuck, and eventually continued brewing another couple days.
I ended up with what smelt like a cheese water. Imagine the water at the bottom of a container of fresh mozzarella. But instead of mozzarella, it was water from a white cheddar. It was not at all appetizing so I did not drink it, but it had all the signs of fermenting properly and nothing to make it seem moldy or like it had gone bad.
I don't measure brix, gravity, or anything like that. I just follow basic brewing principles and use wild yeast.