There are different types of treacle, Black is only one, Golden Syrup is a lighter-coloured type of treacle and often substituted with corn syrup in recipes where black treacle is not available. In Britain, the main producer of black treacle (and Golden Syrup) is sugar refining company Tate and Lyle.
Roasted grapes are sophisticated. Toss grapes with olive oil, salt, and pepper, and roast them on a sheet pan for about 30 minutes at 425Â°F. The grapes will get blistered and caramelized on the outside, and extra juicy and practically jammy on the inside.
I've heard that grapes can contain some oxalates and that apple seeds contain cyanide. The math on these says that if you got a Koi to eat a cubic meter of grapes or appleseeds in a day's time, said Koi could perish from the crystallization of the oxalates in his kidney.