What Temp/amount For The Cool Cube + Late Hops?

[Tanga]

Hi guys,

I've got some cheap 15 litre cubes, perfect for my mini (20L urn) batches. My question is, when making beer with late hop additions (for example the Hobgoblin clone) I would like to boil up a few litres of wort the next day (say 3 litres) for the hops. I saw someone on here post the correct temperature for doing this (in a full batch). I can't remember or find it using the search function, so if anyone else knows how to calculate this it'd be great. I was thinking 9L @ 4 degrees, and mix (slowly so there is no air in the hot wort) with my 3L hop boil this should end up at about fermentation temp, is that right?

Second question is, because I'm not boiling the hops in the full volume, how much more will I need to use? ie, in doing a 3L boil (which will be 1/5-1/4 of the final volume). My understanding is that there is less utilisation, is that a correct assumption?

Cheers!

 

[MarkBastard]

I'm pretty sure argon is the guy to ask, he did 17L in those smaller cubes and I think 3L in some other container, then from memory combined the 17L at about 4 degrees with the near boiling 3 litres and it produced wort at around 20 degrees or so.

From what I understand hop utilisation is more about IBU calculations so with late hops it won't matter that much.

 

[felten]

http://www.onlineconversion.com/mixing_water.htm

 

[MaltyHops]

Great link there felten - seems to work when the page is saved
to local hard disk as well.

BTW - in case anyone is not aware of it, 1 litre of water weighs
1 kilogram so if you need to enter 20 litres in one of the fields
(say), need to type in 20000 grams.