If you know a tame farmer who lets you pick the milkweed he is going to rip up in his cow pasture anyway, all the better. You only need need about 15 flower clusters (umbels) for this recipe. Harvest with care - lots of pollinators and monarch larvae depend on milkweeds (all species, not just this one) for sustenance. I tend to pick one cluster per plant in a large patch.
It's very simple, and similar to the elderflower cordial I have been making for the three summers. As usual, issues of detonation accompany any fermentation, so please read more on the subject.
I recommend Sandor Katz's The Art of Fermentation (Chelsea Green, 2012). Pay special attention to Page 91.
Milkweed Flower Cordial/Fizz
2.5 cups common milkweed flowers, prepped*
2 cups sugar
6 cups water
Peel of 1 lemon, in long strips
*Discard all the stem parts from the milkweed (they contain sticky latex). Keep only the individual flowers. Scissors perform this job quite quickly.
Combine the flowers, sugar, water and lemon peel in a sterilized 1.5 liter jar. Stir well to dissolve all the sugar.
At this point you can either cover the jar's mouth with a double layer of cheesecloth secured with rubber band or string, or leave the lid on loosely. It needs air at this stage.
Fermentation times will vary according to the moods of the wild yeast gods and temperature. But leave the jar at room temperature for about 3 - 6 days. You may stir daily, or not - both ways have worked, for me. If you keep the lid on tightly you should loosen it once or twice a day to allow any accumulated gas from fermentation to escape (this is called "burping"). For the first day or three you may notice no gas accumulation and wonder what the point is. But it should become obvious by day 4 or 5, when the bubbles will form and hissing heard.
Whatever you do, do not walk away from a sealed jar for a few days, do not go away for the weekend, do not forget about it, or you could have a detonation on your hands.
Once the yeast really gets going the liquid will become gassy and the buoyant solids (the flowers) may rise up and out of the jar (like the elderflower cordial, above - elderflower is particularly active). If this happens I leave it another couple of days till things have settled down. Then I strain the flowers off, and gently strain the liquid a second time through cheesecloth. I have bottled the fizz in clean narrow-neck screw top bottles.
Just-bottled elderflower, milkweed and honeysuckle cordials, 2015
These kept well at cool room temperature, but brews can be active, as fermentation has not stopped. The safest place to keep them is in the fridge, as the cold retards or stops yeast activity. Bottles can explode, which is geniunely dangerous.
The bottle I opened today (May 2016) was bottled last May, and was still delicately effervescent.
Milkweed cordial, 2015 vintage
To drink? Dilute with water, prosecco, gin, or whatever else tickles your fancy. Drizzle over ice cream, or fold into whipped cream for an old fashioned newfangled syllabub. And yes, panna cotta. Totally.