23ltr copper -> 30ltr FV

[Hagrid]

I’ve not done a beer in ages and have a 23ltr Copper and I’ve now got a 30ltr FV (Key Keg) if I make 23ltr of wort (with 30ltrs worth of grain), boil and add hops, can I make up the remaining 7ltrs with cool boiled water?

I assume that’s too much head space to leave.

Thanks again.

 

[Drunkula]

It's not too much headspace.

I really wouldn't worry that much about boiling and cooling the water either unless you're getting somewhere super grubby.

If you do top up you'll get an efficiency hit and less hop utilisation but it's not that much of a concern. I used to do 23 litres with a 14 litre boil. For bitterness I'd multiply the IBUs by 23/14 and enter it as a 14 litre batch in brewing software.

 

[Hagrid]

Thanks Drunkula,

If I was to increase grain and hops to 30ltr quantities would I still lose efficiency and hop utilisation?

Thanks again.

 

[AdeDunn]

I used to use a 30 litre FV for 14 litre batches, never worried me, just meant I had more head space for krausen. CO2 from the yeast soon fills up that space no bother. What it does mean is that you never have to worry about blocked airlocks or krausen coming down your blow off tube again... lol

Oh and if you are using decent software, it should have a facility to add water to the FV, and adjust grist and hop quantities for you accordingly in order to maintain target gravity and IBUs for the new target batch volume. I know that the software that I use does.

 

[Hagrid]

True. I think I just had in my head to use the whole space.

Thanks both!