Arb Notes for Oct. 16th: Vitis riparia!

16 October 2008

Vitis riparia! Though the name might be unfamiliar to some of you, the sight of this plant is quite a common thing in the arb. Better known as frost grape, or riverside grape, this ubiquitous vine is just dripping with fruit this time of year. And I don’t know about you guys, but when I see wild fruit this beautiful, my first thought is, “Can I eat that?”

Well, I’m happy to inform those among you who have yet to chance a curious nibble, that the fruit of vitis riparia is quite edible! That’s not to say that they are much like the fat table grapes you can buy at the grocery store, and in fact if you eat more than a few straight off the vine, you might find that your mouth and throat get quite irritated–this fruit has high levels of tartrate in it, a gritty precipitate derived from tartaric acid (the stuff they use to make cream of tartar). But eating these grapes straight from the vine is not where it’s at, so to speak.

If you want to enjoy your wild grapes, your best bet is to make some jam or jelly or wine. The process is simple: get out there and harvest some grapes (they are getting almost perfectly ripe right about now), then put them all in a big tub and gently crush them–don’t break the seeds, as they are quite bitter–then put your crushed grapes in a jelly bag and wring out that juice!

Be careful: if you get a lot of this fresh juice on your skin, the high levels of tartrate could cause some irritation. Just rinse off afterwards. Once you have enough juice, put it in the fridge and let all of the tartrate settle out over the course of a day or two. It will accumulate at the bottom as an ugly gray sludge–just pour off the juice and discard the sludge. Now you’ve got some potent juice.

To make jelly, use 6.5 cups of sugar, 5 cups of undiluted juice, and a package of pectin. Voila! share with your friends, send a jar to the grandparents, spread (hah!) the joy.

Obviously, be sure you can identify this plant before making food with it–there are at least a few similar looking fruits in the arb, all of which are toxic. The fruit of virginia creeper (Parthenocissus quinquefolia), canada moonseed (Menispermum canadense) and even buckthorn (Rhamnus cathartica) could be mistaken for frost grape and these three will make you quite sick. Ask a Naturalist!

Brought to you by your student naturalists: Amy Alstad, Lindsey Nietmann, Jeremy Hayward, David Smith, Hannah Specht, John Vigeland, Katie Blanchard, Chelsea Clifford, John Kraus, Mira Alecci, and Spencer Wigmore.