Am popping a diabolo on later, however the kit calls for 500g sugar, and advised 5% more if using other sugars than white. My can of treacle is 454g, is it worth adding another 71g of sugar, and if so would brown work better?
Black treacle is about 55-60% fermentable so you would need to adjust your figures accordingly. i.e you'd get about 270g of fermentable sugars from the treacle and so would need a additional 230g of sugar. Brown sugar does have a different flavour profile and lends it self to darker beers so it should work well with that kit.
In my opinion it's a better idea to use the black treacle to prime the beer with later, as more of the flavour from the treacle will end up in the final product.
I did brewferms diablo a while back and followed the instructions adding 500g of sugar. The resulting brew only hit 6% when the kit says 8% so i was a little disappointed but it was still a lovely tasting beer. Id add a full kilo of sugars (which i did with brewferms abdij kit which calls for the same 500g and states the same 8% and got a closer 7.5%) if the strength is important to you. Otherwise, yes just top up with a little sugar and im sure youll be pleased with the result.
Similar experience with Diabolo, excellent brew but comes in under the alcohol a bit... I worked out at around 7% rather than the 8% optimum; though the strength in flavour was there. I too would consider adding the greater amount of sugar and the treacle later if it's the flavour you're looking for from it...
I ended up having to put the treacle in now, forgot to check what sugar i had left, and only had about 300 grams of brown left; ended up with an OG of 1.070.
What kind of fg should I expect? Is the kit likely to be a sticker?