I'm doing an Epic Pale Ale clone with this partial grain kit. The kit includes two un-hopped liquid malt extract cans. Sterilisation aside, I want some clarification as to whether you should boil un-hopped malt extract.
In Randy Mosher's awesome Radical Brewing book he seems to say you do boil it:
If you're an extract brewer, somebody has done all this work for you, and this is where you take over.
The wort is transferred to a kettle and brought to a boil...
Looking at the Black Rock extract website, their process shows that they already boil when making the extract.
The Beer and Wine Journal says:
Extract brewers should boil the largest volume of wort they can manage, up to a full-wort boil. The more volume you boil, the less color pick up you will get. In addition, the corresponding lower specific gravity will increase your hop utilization.
but then in the very next paragraph:
Brewery grade malt extract has already been boiled. It does not need to be boiled again.
On here user jsled said (see also brewchez's commnent)
You do need to boil the hops in the presence of wort sugars to isomerize the hop oils to get bitterness.
So there seem to be two questions emerging here.
- Do you need to boil un-hopped malt extract? Why?
- Do you need to boil hops in the wort? Why?
Apart from jsled's comment about isomerization, all the other suggestions about boiling extract seem to be "boil it in as much water as possible" to get around the hop utilisation issues and colour pickup issues. If we get better hop utilisation boiling with lower SG, then the lowest of all will be... water. If we just don't boil the extract at all can't we simply avoid these concerns entirely?
For my two-cents, the best home-brew I ever made was a partial grain IPA where I didn't boil the extract and boiled the hop schedule separately in water. Even my sweet-mouthed malt-loving friends thought it was great. I'm sure Randy would approve as long as it tastes good, but I'm interested in understanding the chemistry.