Maximum safe boil volume

[soupdragon]

Hi all
I have a stockpot that holds 15ltrs to the brim. What would be the maximum volume I can safely boil allowing for head space and foaming? If for example it's 13, roughly how much would be left after a good 90 min rolling boil? Stockpot is 28cm wide at the brim and 24 high ( give or take a small ammount ).
Cheers Tom

[OldSpeckledBadger]

Personally I like a 2 to 3 inch gap until the boil is well established. I then top it up a bit with boiling water.

[minimilo]

I have got a 15 litre stockpot and I would not put more than 10 litres in it.

[soupdragon]

I suppose the best thing is to play it safe and just see how much I can get away with then top up as the boil progresses. I remember from my old brewing days that the boil can be quite foamy till things settle down
Thanks for the advice Tom

[OldSpeckledBadger]

Assuming you're doing a partial boil brew 15 litres should be more than enough capacity for a 23 litre final brew length.

[soupdragon]

Assuming you're doing a partial boil brew 15 litres should be more than enough capacity for a 23 litre final brew length.

Yes, I'm planning on following your method as best as I can. I've just about worked out how to adjust my dried malt addition to maintain the ebu called for in the recipe with Graham's beer engine. I've based the volume on 13 ltrs, do you think that's a bit much for the 15 ltr pot to cope with?
Cheers Tom

[OldSpeckledBadger]

13 will probably be OK if you top it up once the boil has settled. BTW you do know that your EBU needs to be proportionately higher than target because you'll be watering it down at the end? For instance if you need 23 litres at 30 EBU in the FV and your boil is 13 litres your EBU in the boil needs to be 30 * 23 / 13 = 53.

[soupdragon]

Yes, I've been doing tons of research. Once the penny dropped, I've found the beer engine to be most usefull
Cheers Tom

[soupdragon]

Mr Badger
As a side question...........
Is your recipe for Brock's Bostin' Black Country Mild ( just searched for it ) anything like Moorhouse's Black Cat? And please don't say, yes it's dark
Cheers Tom

[OldSpeckledBadger]

Is your recipe for Brock's Bostin' Black Country Mild ( just searched for it ) anything like Moorhouse's Black Cat?

I've never heard of Moorhouse's Black Cat let alone tried it so I have no idea.

[soupdragon]

Moorhouse's are a Burnley brewery and their mild, Black Cat is an outstanding brew ( won many awards ). Only ever had it from the brewery tap when visiting Burnley tho
I'll have to brew yours and try it for myself
Cheers Tom