I've recently started making simple desserts consisting of milk, sugar, flavoring and gelatin. Last time I tried using frozen raspberries as flavoring (around 1:10 raspberries to milk by weight) and the milk curdled. It still tasted good, but the presentation was less than appealing. Is there some ingredient I can add to the mix or some special technique I can use to prevent curdling?
As long as the last step is "bring to boil, mix in gelatin and set aside", I think, that any process will work.
One obvious solution I want to avoid is neutralizing the acid with a base. I don't like this, because I would need to adjust the amount of the base to the acidity of the flavoring: if I overdo it, then milk will curdle from the alkalinity, if I underdo it, then it will still curdle from acid. It's too precise for my liking if there is another solution available.
This was my experience using soy milk, but I've found people on the Internet saying it happened to them with cow's milk, so "milk" in this question refers to both cow's and plant milk. I use both soy and cow's, so I'm interested in answers for both.