Hop utilization and boil volumes

[MedicBrew]

Sorry if this has been asked before, I search and seemed to get opposite answers to the same question.

I've taken a break from brewing the last two years, used to do biab all grain batches, now with a kid I'm looking for something a little quicker but never really worked with all extract batches before. I'll be doing at most 3gal boils on the stovetop (ie, quick)

I'm brewing a big pliney the elder cause why not. 1. How does less volume of water effect hop utilization? Less right? More hops? Any other way to get the same bitterness, do extract brews just use more hops or do people not account for this?

2. Adding all the dme at the beginning or half at 60, half at 15. How does that effect hop utilization? And are there any differences in flavor doing it this way. Obviously less caramization with such a high gravity boil but is that it, and color?

Maybe I'm wanting my cake and eating it too by doing a partial volume big beer?

 

[shanecb]

I don't think, volume-wise, you're going to really see much of a utilization difference at the homebrew scale either way. Scaling up to pro-sized batches of several barrels might only get you a 10% increase (there's no magic number, though). I wouldn't take it into consideration for homebrew.

Wort gravity affects hop utilization some. It's not a solubility issue as most people used to think. The more solids there are in the boil, the more "things" the alpha acids have to stick to, so they won't be free in the wort. The table of this page gives you an idea: http://howtobrew.com/book/section-1/hops/hop-bittering-calculations That whole page is worth a read, too.

 

[MedicBrew]

Thanks for the reply. That was an interesting article, it starts off by looking at how utilization is different because of the higher gravit wort, but then doesn't even address what happens to that wort once its diluted with water in the fermenter.

This site: http://beerandwinejournal.com/extract-boil-volume/ seems to suggest that diluting at the end means those IBU's are directly linked, double the water, half the IBU's. If thats true, how-to-brew spent a long time figuring out how utilization changes during the boil but not how much bitterness you end up in the finished product which is the only point that matters.

 

[MedicBrew]

I have to wait for a moderator to approve my comment, presumably because I included a link, so I'll just decide on this brew as i go I guess.

 

[Yooper]

We're usually pretty quick at approving.

The dilution advice from beerandwinejournal is spot on- it's not the concentrated boil that impacts the utilization much. It's the dilution. Since the max of isomerization that can happen is less than 100 IBUs no matter how many hops are added, it just follows that the IBUs are lowered when water is added.

Here's what I mean. Let's say you boil 2.5 gallons of wort and managed to add enough hops to get 100 IBUs in that wort. (That's debatable, and it's probably more like a max of 85-90, but 100 makes my math easier.

So, you have 2.5 gallons of 100 IBU wort and you're making a 5 gallon batch. So that's 2.5 gallons of 0 IBU wort to add to it. Right there, that means the max you could get is 50 IBUs. Coupled with the fact that it's more likely to me 85 IBUs at a max, and you'd need a lot of higher IBU hops to get that, it's far more likely to be in the 40-45 IBU range.

That's not a problem for most ales or lagers, but in a big IPA or a big barleywine, it can big a big issue.

 

[MedicBrew]

We're usually pretty quick at approving.

The dilution advice from beerandwinejournal is spot on- it's not the concentrated boil that impacts the utilization much. It's the dilution. Since the max of isomerization that can happen is less than 100 IBUs no matter how many hops are added, it just follows that the IBUs are lowered when water is added.

Here's what I mean. Let's say you boil 2.5 gallons of wort and managed to add enough hops to get 100 IBUs in that wort. (That's debatable, and it's probably more like a max of 85-90, but 100 makes my math easier.

So, you have 2.5 gallons of 100 IBU wort and you're making a 5 gallon batch. So that's 2.5 gallons of 0 IBU wort to add to it. Right there, that means the max you could get is 50 IBUs. Coupled with the fact that it's more likely to me 85 IBUs at a max, and you'd need a lot of higher IBU hops to get that, it's far more likely to be in the 40-45 IBU range.

That's not a problem for most ales or lagers, but in a big IPA or a big barleywine, it can big a big issue.

Ok thanks, so big IPAs are pretty much full boil or suffer some lack of bitterness which I am ok with. While I know perceptable bitterness maxes out at 100IBU, is that the case for the max isomerization of the wort itself? Has that been studied? If I create a theoretical 200IBU (meaningless to us mere mortals), but dilute it 50%, are we sure I dont end up with 100IBU, and not 50 based on limits. (The limits being my 200IBu is really only 100 since that is all the hops will cling to). I guess I am getting pedanatic, but are we really saying there is theoretically no way to make a partial boil volume a max 100IBU'ish despite the amount of hops?... doesnt seem right.

 

[MedicBrew]

P.S. Brewed my pliney tonight, biggest surprise was having to deal with my second hotbreak at 15min as I added the rest of the DME. Did a 4 gal boil and got away with it on my stove.

 

[Yooper]

Ok thanks, so big IPAs are pretty much full boil or suffer some lack of bitterness which I am ok with. While I know perceptable bitterness maxes out at 100IBU, is that the case for the max isomerization of the wort itself? Has that been studied? If I create a theoretical 200IBU (meaningless to us mere mortals), but dilute it 50%, are we sure I dont end up with 100IBU, and not 50 based on limits. (The limits being my 200IBu is really only 100 since that is all the hops will cling to). I guess I am getting pedanatic, but are we really saying there is theoretically no way to make a partial boil volume a max 100IBU'ish despite the amount of hops?... doesnt seem right.

Yes, the amount of hops oils that can be isomerized before the wort being saturated is a bit less than 100 IBUs. Even Pliny the Elder, which calculates out to 250+ IBUs has been measured in a lab at 85 IBUs.

However, there IS a way to get more IBUs in wort- those concentrated hop extracts like HopShot. According to the manufacturer, you can get a full 100 IBUs in wort if you use enough of it. https://www.northernbrewer.com/documentation/hopshot.pdf

 

[MedicBrew]

Ah yes I forgot about that. Again though you would be using hoptshot at 60min or so for bitterness... then still diluting. So max bitterness means no dilution, full 8 gal boils I think. Interesting that Pliney was measured to be 85, that answers the question of what is actually being saturated into the wort.

 

[shanecb]

Thanks for the reply. That was an interesting article, it starts off by looking at how utilization is different because of the higher gravit wort, but then doesn't even address what happens to that wort once its diluted with water in the fermenter.

This site: http://beerandwinejournal.com/extract-boil-volume/ seems to suggest that diluting at the end means those IBU's are directly linked, double the water, half the IBU's. If thats true, how-to-brew spent a long time figuring out how utilization changes during the boil but not how much bitterness you end up in the finished product which is the only point that matters.

Oh, wait, sorry. I might not have read your question correctly. I didn't realize you were asking about how diluting with water would affect things. I thought just hop utilization. My mistake.

 

[MedicBrew]

Oh, wait, sorry. I might not have read your question correctly. I didn't realize you were asking about how diluting with water would affect things. I thought just hop utilization. My mistake.

No your reply was totally valid. How-to-brew started that article with this...

For a 5 gallon recipe, we will boil 1.5 oz of Perle hops for 60 minutes for Bittering and 1 oz of Liberty for 15 minutes for Finishing. The recipe calls for 6 lbs. of dry malt extract and it will be boiled in 3 gallons of water because of the pot size. The remaining water will be added in the fermenter.

My point is that part I put in bold makes all of their results fairly meaningless, they missed the point of what they were studying. They are studying how increased wort gravity (because of their smaller volume boil) might affect how the hops are utilized... and then skip how they dilute all that wonderful utilized hoppy wort into water negating all the rest of it.

Its interesting to see the relationship between gravity and hop utilization, which is a negative relationship as it gets higher. Combine this with partial volume boils and I can see how we lose a lot of bitterness with extract brews. I will see how my pliney comes out as I have done it with a 7.5 gallon all grain method and know how well it came out. I have used the same amount of hops this time around with only a 4 gal boil, and a split grain bill (well, DME bill), along with a couple gallon top up in the fermenter. Plenty of room for lost IBU's in this scenario but we'll see if it actually makes any difference.