for ~1.040 I use 1 oz of DME for every cup of water (1:1 ratio of pounds to gallons). A liter is just over a quart, but it'd be roughly 4 oz DME for a liter of water, or 115ish grams. Make a liter (or quart) of wort, cool it, whip the everlovin crap out of it with a sanitized wisk, toss it in...