I’ve been learning about this…. and trying to perfect my brewing so as to minimise loss.

Brewing comrade Kevnlis explains it all quite well over in a thread at Geoff & Oliver’s forum

But here is the nuts and bolts of it…

Basically, when making an extract brew, we need to add our own hops. Kits come already hopped.

The bitterness that we seek from the hops is extracted best in fermentable sugars, such as the malt extract we are making our wort from. To get the most out of our hops there is a formula to use, and here it is:

x = volume of water you will boil in, eg: 4Lt
y = batch volume, eg: 23LT
z = total amount of fermentable sugars to be used in the batch, eg 3 kilos
f = amount of fermentable sugars to be used in your boil, eg: 522g

f = (x/y)*z

It gets a little more complicated than this, so its best to read the thread mentioned above. Using the example data above this is what our equation would look like:

f=(4LT/23LT)x3kg

f=522g

So however much hops we choose to use needs to boiled up with 522g of malt extract (or whatever fermentable sugar we are using).

As I mentioned it gets a bit more complicated when you start to look into levels of yield, but a god piece of software like Promash will help here.

Hope this helps….