Tartaric acid is very bitter, so the quantity is crucual. I am zeroing in on it, but am not there yet. All of these experiments have been using 1 US pint of heavy cream (2 cups, 16 fl oz).
The basic ratio has been to use 4 oz sugar per recipe also. However, the chocolate experiment didn't have added sugar because the chocolate should have been sweet enough - it wasn't!
Experiment 1 - Pink peppercornsThis was in many ways the easiest recipe, but ot really brought home the bitterness of the tartaric acid. Here I used a (US) pint of cream, 4 oz sugar, 1/2t tartaric acid dissolved in a little sugar syrup (ginger flavored). This set up beautifully, but was dedinitely bitter.
Experiment 2 - ChocolateThis one was Ok, but I messed up by using too much espresso powder in an attempt to boost the chocolate. For 1 (US) pint of cream I used 4 oz sugar, 1 whole disc of Ibarra chocolate, 1/4 t tartaric acid and 1t espresso powder dissolved in hot water. Set up fine. But again was a bit bitter. The coffee was overwhelming. The texture was nice though.
Experiment 3 - OrangeThis one did not set up properly. Shame because the flavor was superb. Here the 1 (US) pint of cream, 4 oz sugar, finely grated zest of 3 oranges in the base and then juice of 1 orange 2T Grand Marnier and 1/8t tartaric acid. Clearly not enough tartaric acid to get the set that I wanted.
Experiment 4 - Kaffir lime/gingerAgain, terrific flavor, Perhaps my favorite. 6 fresh jaffir lime leaves (from tree in garden), a 2 inch chunk of ginger minced finely + 1 (US) pint cream and 4 oz sugar. 1/4t tartaric acid in ginger syrup. Surprisingly didn't set up quite enough, But probably my favorite in terms of flavor.
My local Tom Thumb now has an official cream shortage!