why need boil the hop in different timing?

[shawn]

Hi, I'm still new to homebrew and did few batchs, I am wondering why most recipe require to boil different hop at different timing? I tried boil single hop at 15 minute only, and I think is still ok.

If the timing is for the flavor and bitterness, how to tune the timing? any specific guideline？

Thank you so much for any comments, thanks.

 

[BreadMurderer]

http://howtobrew.com/book/section-1/hops/how-are-they-used

That's a nice little article on it.

EDIT: Just realised his website has had a lick of paint! Nice.

 

[clibit]

If you boil hops for 60 mins you get mostly bitterness - the flavour boils away.

If you boil for 30 mins, you get about half the bitterness, and some flavour.

If you boil for 15 mins, you get mostly flavour, and some bitterness.

If you add the hops after the boil, and steep them, you get lots of flavour and aroma but only a small amount of bitterness.

If you add the hops after the beer has cooled below 80C, you get flavour and aroma but no bitterness.

 

[Hoddy]

The amount of bitterness that you get from a variety of hops is gauged by the alpha acid % and you can find out if a variety is more of a bittering or aroma in their use. With clibits reply that should answer your question.

 

[geetee]

You will be familiar with the alpha acid for each hop. This really is a measure of potential bitterness only. The alpha compound is not inherently bitter but during the boil it isomerises to give the iso alpha acid which is bitter. So you do need the 60 minute boil to isomerise the hop content and release the bitter.

it is also worth noting that even with 100% fresh new hops the maxium bitterness you will probably utilise is 25 - 30%. As the hops age through a season this will reduce so really when you calculate an IBU it is really a best guess.

Late hops, say 15 minutes, will not have time to fully isomerise so you may get 25% of the initial hop bitterness, that is 25% of the 30% you started with so 7% contribution maybe. Late Hops added at low temperature (less than 80C) will bring flavour and aroma but being unable to isomerise will add no bitterness.

So its best to use fresh hops properly stored where you can and even then it is an estimation of potential utilisation. You can repeat a recipe later in the year with hops almost a year old and their utilisation will have dropped. There is one up side in that the alpha acid breaks down to the beta acid which itself has some bitterness but not as much.

 

[shawn]

Thank you so much for all the information, thanks...

 

[mike77]

So I'm wondering why we bother with late additions at all and not just go for a 60 min bittering addition and a big post boil addition?

Theoretically this would give maximum potential from the bittering and the flavour/aroma hops and would require less hops being used.

 

[geetee]

This is exactly what some people do, it's horses for courses.

I went through a phase of late additions at 15, 5 and steep hops, maybe dry.
For some recipes this makes a big difference for others I have struggled to find the hops. I am not convinced that leyering hops at intervals has a big impact.

Americans set a lot of store by what you say and pile all in hops late or steeping at end of boil for maximum hop flavour and aroma. I have lately adopted this approach including dry hopping and find it just as good if not better.

 

[mike77]

I've been doing a bit of reading on this. I think my next beer I'm going to set the IBUs from the 60min addition then add add half of the flavour/aroma hops after i have started cooling and then steap them at 65c (maybe). Then use the other half for dry hop.

 

[geetee]

Sound strategy.
This is how you find out what works by trial and error and as long as you can still drink the end product you are learning all the time!

My last ale had 3 different hops at 5 mins (25g each) a further 50 g steeping for 20 minutes and then 50 g dry hop once fermentation is calming down.

Now in the fridge chilling and it smells Awesome (to quote the yanks!)