What does the boil do to extract?

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DNW

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Newb alert! I've done some searching but can't find the answer...

If it's been posted somewhere, please just point the way - no ned clogging up the forum with extra info.

I assumed that boiling for 60 minutes was primarily to get the flavoring hops developed and do "something" to the extract. This was probably due to the fact that the first two recipes I did called for putting all the extract in at 60 minutes. Now I've seen recipes that call for some extract added at 10 or 15 minutes and references made to the fact that it will help keep the color lighter. My question is, if you're doing a light (colored) beer, such as a hefeweizen, why would you boil the whole bill for 60 minutes if it's going to make it darker than necessary? I'm assuming there IS as reason, but I can't figure it out...

TIA-
 
Short answer is that boiling hops in just plain water is not efficient (see low hop utilization). By adding some extract in at the beginning of the boil, you help to extract more bitterness from the hops
 
You boil the extract/water mix to get the hops to properly flavor the beer.

However, there are no boil extract kits that you add nothing to. Mistake I made on very second brew was to boil an IPA kit--ended up as smooth easy drinking beer and not an IPA...

That said, you do boil all water prior to going into fermenter... No boil kit = boil and cool your water first to take care of anything in it (well water) or off-gas chlorine (city water).
 
So there is no detriment to hold half the addition until late in the boil? How late can you wait, and how much could you hold back without having enough ME to affect the hop flavor extraction?
 
So there is no detriment to hold half the addition until late in the boil? How late can you wait, and how much could you hold back without having enough ME to affect the hop flavor extraction?

The lower the specific gravity of the boil, the better the hops utilization. So, it you hold most of the extract until the end, a good rule of thumb is to decrease the bittering hops (only those hops, not the later ones) about 25%. What helps to really get the right amount hops bitterness (IBUs) is to use some brewing software. That way you can adjust the amount of those hops to get exactly the bitterness the recipe initial planned.

This "late extract addition" is a relatively new technique, so many older books don't have the information. John Palmer and Jamil Zainasheff's newest book, "Brewing Classic Styles" does use this technique, though.

The extract has already been processed, so it doesn't really need to boil. I guess it could be, to sanitize it, but as far as for beermaking it doesn't really need to be.
 
Interesting toppic, thanks for posting the question and the replies. Thoughts to ponder on my next brew. I don't think I'm up to AG yet, so these ideas and techneques help with the mind and experimental thinkings I have in my head.

Love this hobby!
Cheers
 
Specifically, the 60 minute boil is for the bittering compounds to isomerize & dissolve. We call this utilization.

It's important to understand that bittering and hoppiness (flavor & aroma) are very different things.
 
The lower the specific gravity of the boil, the better the hops utilization. So, it you hold most of the extract until the end, a good rule of thumb is to decrease the bittering hops (only those hops, not the later ones) about 25%.

So...it seems a win/win situation. Maybe I'll have to check out brewing software. I'm sure there must be a section on the site that deals with it so I won't divert the discussion here.

Thanks everyone for all the info!
 
I had a similiar question as this earlier. I found out beersmith has late extract options to help you figure out your IBUs if you want to be scientific.
 
Yeah, I am doing a lighter colored ale and planning on doing the late extract addition (25% at the start, 75% fifteen minutes before the end of the boil). The advantages are less caramelization (and lighter color) and less twanginess (from less scorching of the LME). It also makes for a clearer ale.

I knew the lower SG of the wort, the more isomerization (I think this is the right term) will happen to the hops (therefore more bittereing). Good to know about decreasing the hops by 25% as a rule of thumb. I don't have brewing software.

Thanks.
 
I don't decrease the hops myself for most styles, but I tend to like a little more hop flavor anyway.
 
Is wort required at all during the boil to utilize the hops?

If so, is the ratio of 25% wort in the boil maximally efficient at utilization? It seems that
if wort does not play a crucial role in utilization that it would make sense to minimize the
amount of extract added to maximize utilization, and then add most or all of the extract
with just enough time to fully dissolve it.

Edit -
I'm assuming the hops won't be utilized in average PH water so some wort is necessary.
 
According to Palmer, utilization is a function of two variables - 1) specific gravicty of the actual medium that the hops are in, and 2) time the hops spend in that mix.


Utilization = f(G) x f(T)
where:
f(G) = 1.65 x 0.000125^(Gb - 1)
f(T) = [1 - e^(-0.04 x T)] / 4.15

So yes, it does seems that utilization would be maximized by adding NO extract until the very end of the boil. Of course, you have to account for this better utilization by adjusting the amount of hops and/or the time that they are added.

This would also suggest that it would be possible to do a boil (or partial boil) in less than an hour. There must be some other drawbacks. There could also be some benefits from minimizing the amount of time the extract boils.
 
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