Summertime Cerulean Blue Sauce
Medieval Kitchen, p. 168, From Libro de arte coquinaria.
Sapor celeste de estate
Piglia de li moroni salvatiche che noscono in le fratte, et un poche de amondole ben piste, con un pocho di zenzevero. Et queste cose distemperatai con agresto et passarale per la stamegnia
Sky-blue sauce for summer
Take some of the wild blackberries that grow in hedgerows and some thoroughly pounded almonds, with a little ginger. And moisten these things with verjuice and strain through a sieve.
Medieval Kitchen’s redaction:
1 quart (1 liter) blackberries
1/3 cup (50 g) unblanched almonds
2/3 cup verjuice, or a mixture of two parts cider vinegar to one part water
1/4-inch slice ginger, peeled
Puree the blackberries in a food processor or food mill, and strain the juice, pressing to extract as much liquid as possible. In a mortar or in a blender, grind the almonds and ginger, then mix with the blackberry juice. Contact with the air will turn the mixture a dark blue. Add the verjuice and strain once more. Season with salt to taste.
This didn’t come out blue. It came out a very deep berry red. It -might- have turned blue if I’d added water to it and then strained out the berry meat. It just seemed a shame to waste all that berry meat so I left it in.