Jam making

We’ve tried making a variety of things since we got here; bread, scones, shortbread, lemon curd etc. which have generally been edible - some even quite good. So with the hedgerows full of brambles Linda decided to try her hand at a bit of jam making today… Blackberries, sugar and heat were all that was required - not sure what when wrong - but we ended up with a saucepan full of burnt toffee. Maybe too much heat for too long? Advice gratefully received – Ros?