The science of hop pitching

[pdrewcock]

Hi all,
I'm fairly new to the art of brewing. I have MADE beer for many years, but only recently begun to pay close attention to what I'm putting in it. ie: going beyond the basic recipe.
So I got to wondering in my double IPA fog, if boiled hops are for bittering, and dry hopping is for aroma, why are some recipes written to pitch hops 1/2 an oz at a time 10 minutes apart in the boil starting from 60 minutes until flameout. Is this actually an art or just a whim? Sometimes it just seems random, and in fact I watched a video where the brewers rolled dice for the times that the hops were pitched. Why aren't all the hops pitched at 60 minutes to maximize efficiency? Am I being kinda crude here? Maybe my tastebuds aren't fully developed yet.
Cheers! Pete D.

 

[Sbarnard80]

Curious about this myself. I would think it must be that it's not just about extraction. The hop oils change over time and you get different degrees/layers of hop bitter and aroma flavors. Wondering about what someone with more science behind this has to say.

 

[Dan]

Welcome to HBT pdrewcock.

Somebody among this crowd of great brewers will give a better explanation than mine. Thank goodness.

Hops are added at different times for a reason. The ones thrown in as soon as the boil starts are called bittering hops. The ones thrown in halfway through impart some flavor and the ones at the end give IPAs especially the nice aroma. (I could have these last two turned around) Point is, the longer the hops are in the boil the more they contribute to bittering and less to flavor and aroma. So there are various hops scheduling times dependent on the required taste of the beer.

 

[pdrewcock]

Welcome to HBT pdrewcock.

Somebody among this crowd of great brewers will give a better explanation than mine. Thank goodness.

Hops are added at different times for a reason. The ones thrown in as soon as the boil starts are called bittering hops. The ones thrown in halfway through impart some flavor and the ones at the end give IPAs especially the nice aroma. (I could have these last two turned around) Point is, the longer the hops are in the boil the more they contribute to bittering and less to flavor and aroma. So there are various hops scheduling times dependent on the required taste of the beer.

So how does one learn the science of this wonderous technique? Must one climb a mountain and consult the sages or is there an app for that? Sorry if I sound trite, but it's not obvious, and I really want to learn.
Cheers! Pete D.

 

[Beezer94]

http://www.howtobrew.com/section1/chapter5-1.html

The howtobrew website is an online copy of the book 'How To Brew' by John Palmer that many homebrewers started with. Lots of good information to get started with.

Just know that a lot of brewers think there is only one right way to do things; until enough people get better results some other way.

http://www.mrmalty.com/late_hopping.php

 

[Marc77]

The other way of doing things is first wort hops which some swear by. It's also discussed in Palmer's book. There's all sorts of ways of adding hops but the basic is that hops will release their oils and the earlier in the boil the more oils that get into the wort. By default the oils won't "blend" well with the wort but the longer you boil them the more they "blend". Don't know the scientific term for "blend".

Dan was right with what he said, early for bittering, mid for flavor and late/dry hopping for aroma. First wort hopping is throwing the hops in at a certain time before you start your boil/are sparging. Palmer's "How to Brew" book is a great place to start. It's online and free to boot! When you want to know more there's a book called "For the Love of hops" by Palmer that's part of a trilogy of books. Water, hops and yeast are the three books. Everyone that's read them has come away with so much knowledge it's ridiculous. I've heard they're "hard to read" in that you read them, stop and digest and then read some more.

 

[Mobeers]

So I'm no expert but I think I understand where the OP is coming from. It sounds like he has a firm grasp in the current model of thinking in adding hops for different reasons at different times but is challenging that idea. Why not all buttering hops at 60 instead of some at 45 and so on. Kind of like a modern day Christopher Hopolus sailing into a flat world! Just my 2 cents!!


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[AlCophile]

Can you folks access the free online Chemistry of Beer course, already underway, through the U. of Oklahoma?
It is on some platform(?) called Janux, and I cannot get it.
You can get the url by searching this forum. Good luck.

 

[TallDan]

So I'm no expert but I think I understand where the OP is coming from. It sounds like he has a firm grasp in the current model of thinking in adding hops for different reasons at different times but is challenging that idea. Why not all buttering hops at 60 instead of some at 45 and so on. Kind of like a modern day Christopher Hopolus sailing into a flat world! Just my 2 cents!!

Because it's a sliding scale. Assuming that adding all hops at the start of the boil or at the end is somewhat like assuming that all beers are either an imperial stout or a light lager and nothing in between.

It's not a black and white kind of thing. There is black and there is white, but in between there's a whole rainbow of color.

Similarly, you can't just average out the hop additions and expect the same results. Putting one ounce of hops in at 60min and one ounce at flameout is different than adding two ounces at 30 minutes.

But! If you don't want to take my word for it, and don't want to read the books as others suggested, one of the best thing about being a homebrewer is that you don't have to! It would probably be an interesting and educational experiment to do with some small batches of an APA:

Batch 1: 4oz hops added at 60 min
Batch 2: 4oz hops added at flameout
Batch 3: 1oz @60min, 1oz @30min, 1oz @5min, 1oz @flameout
Batch 4: 4oz @23.75min (average of Batch 3 additions)

Unless you prove conventional wisdom wrong, batch 1 and 2 are probably not going to be great beers, but they will teach you what additions at those points do to the flavor of the beer.

 

[Mobeers]

I Definitely agree with and have read the books suggested. What I do think is important in home and craft brewing is to push the envelope. example: first wort hopping. relatively new technique that may have gotten frowned on five years ago. Or maybe the school of thought that is gaining traction in that the use of a secondary after fermentation is complete is essential for dry hopping or other additions . I think what makes home brewers unique is the amount of flexibility that we have. Got a new idea or technique to try; IE SMASH brewing, new fruit additions or first wort hopping. Its just a few gallons if its bad. A BMC brewery probably wouldn't dream of it, they'd need to dump thousands of gallons if its bad. I ramble. I think the OP is Just challenging conventional wisdom and not the science. Bottoms up!

 

[edgeoftheUS]

Everything I needed to know about hops i learned from Mitch Steele's (founder of Stone) IPA book.

http://www.amazon.com/IPA-Brewing-Techniques-Recipes-Evolution/dp/1938469003

okay, not everything but he did pave the way for craft breweries, posts all of their recipes online, and goes through all of the hopping techniques and gives examples to compare to such as RR Pliny, Dogfish, Stone, etc.

 

[Calder]

I don't think he is challenging anything; just wondering why people do different things and is there a way to measure the effect.

Every hop you add except dry hops will add to the bitterness. The earlier you add them, the more IBUs they impart. Measurement is a relative measurement, and everyone will get different results. There are some tools to help measure the IBUs, but they are not absolute, just approximations, and different people prefer using different programs for it.

Although you get more IBUs, the longer you boil, some feel you get a harsher bitterness with a longer boil. It is a journey to discover what you like. Me, I usually add a small charge at 60, and use a lot of hops spread out from 15 minutes in to get my IBUs. This way I get more flavor and aroma too, but I do use more hops than you will find in a basic recipe.

Late hops give flavor and aroma. Generally late hops are added at 15 minutes to go. More flavor at 15 minutes than aroma, and more aroma at 0 mins. You do get some flavor with the early hops, but not much.

 

[Marc77]

First wort hopping is actually a much older technique that we "rediscovered" recently.

 

[splattsmier]

It's all about the acids and oils.

Hop acids/oils contribute bitterness, flavor, aroma, and can even effect head retention. The delicate hop oils boil off the longer they are in the kettle, aroma being the first to go. That's why aroma additions are late kettle/flameout/whirlpool or dry hopped. Flavor additions are added toward the end of the boil (say, 20-5 min left).

As mentioned earlier it's a sliding scale, so different addition times will contribute different combinations and with different intensity.

Hope this somewhat simple explanation helps. Welcome and cheers!

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[pdrewcock]

Thanks to all for your explanations and links. I have much to learn, but it's beginning to make more sense.
Cheers! Pete.

 

[SilverZero]

I found this post pretty well-written - and it has pictures!

Just to add to the info a couple of posts up: If you add hop-stands to all of these techniques, you will get aroma and/or flavor without adding any IBUs because the temperatures at which you steep are below the isomerization levels for the alpha acids (or, at least, low enough that isomerization is greatly slowed down - can't stop kinetics!). I do 40 minute hop stands at 150F-160F.

I tend to FWH for most of my IBUs using a hop that complements my late hops, as there will be some flavor imparted. If I'm using a super-high AA hop like Summit, I'll just do a 60-minute boil to avoid getting its flavors. I never add anything else before 15 minutes, and typically only in the last 10 minutes (especially if I FWH). I do big hop stands and usually dry hop as well, since I typically make APAs and IPAs. Because I want to.

 

[IvanBrew]

Hi all,
I'm fairly new to the art of brewing. I have MADE beer for many years, but only recently begun to pay close attention to what I'm putting in it. ie: going beyond the basic recipe.
So I got to wondering in my double IPA fog, if boiled hops are for bittering, and dry hopping is for aroma, why are some recipes written to pitch hops 1/2 an oz at a time 10 minutes apart in the boil starting from 60 minutes until flameout. Is this actually an art or just a whim? Sometimes it just seems random, and in fact I watched a video where the brewers rolled dice for the times that the hops were pitched. Why aren't all the hops pitched at 60 minutes to maximize efficiency? Am I being kinda crude here? Maybe my tastebuds aren't fully developed yet.
Cheers! Pete D.

It's an art if your understanding of it comes intuitively, but if you're inclined to research and study, it is much more a science...

The bitterness imparted by hops comes through isomerization of the alpha acids. Isomerization happens during boil, and the longer you boil, the more alpha acid is isomerized.

Flavor and aroma is largely (but not completely) imparted by the beta acids in hops, which do not isomerize during the boil. In fact, they are more volatile, and are driven off by boiling.

To retain flavor and aroma, the boil time has to be short.

This is a horrifically over-simplistic view. There are hundreds, if not thousands, of compounds in hops that contribute to flavor and aroma. According to Wikipedia (which no academic would ever cite, lol), "about 250 components of essential oils have been identified."

The shorter answer, as others have mentioned, is that the longer you boil, the more bitterness you impart. The shorter you boil, the less bitterness and more flavor/aroma you get. Dry hopping is almost entirely about aroma, but aroma definitely affects perception of flavor...

Alright, now even I'm confused. I need to go have another beer...

 

[Buna_Bere]

science and beer colliding, long live iipa's