Why don't we boil hops separately?

Skyfloater

I was doing an all grain mash and boil today, when a recurring question popped up. Namely, why is there a need to boil the wort and hops for the full hour?
Is there a reason why we don't just bring the wort to the boil briefly to sterilize it and boil the hops separately on the hob?
Can anyone enlighten me, thanks.

BeerNut

Isomerisation. The molecular structure of the hop flavour compounds change as they're boiled with wort. It's how the bittering/flavour/aroma effect works.

Skyfloater

BeerNut wrote: »

Isomerisation. The molecular structure of the hop flavour compounds change as they're boiled with wort. It's how the bittering/flavour/aroma effect works.

Thanks, I thought it was something like that.

sharingan

there is more to it of course, saturation of iso alpha acids hits a ceiling that makes it impractical to get your bitterness from small boils. i.e. you cant get 30IBU by boiling your hops in 10% of your wort.

Also, the boil removes proteins from the wort (hot break + precipitation) which is a desirable outcome.

loyatemu

you're free to play around, a shorter boil will still give you beer but it may have a different flavour profile.

60 minutes has been considered the minimum to boil off DMS (off-flavours from the malt) but supposedly that's not a major issue with modern malts. The bitterness can be upped by increasing the hop quantity or using hop oil.

Brulosophy have done tests on altering the length of the mash, boil etc - their conclusions are often that a lot of the received wisdoms of homebrewing are bunk. This is one they specifically did with a short mash and boil: http://brulosophy.com/2017/06/26/traditional-vs-short-shoddy-brewing-process-exbeeriment-results/