Increase Hop Utilization by adding Extract at end of Boil?

I've recently come to understand that the more malt extract there is in a wort, the less the hops are fully utilized. Unfortunately, I don't have a large kettle.

Using BeerSmith, I calculated 5 oz of Amarillo in a 4 gallon batch (using a 1.78 gallon preboil and topping off at the end) resulted in only 38 IBUs. However, if I lower the Pilsner extract from 6.5lbs to 3 lbs the IBUs increase to 75....according to Beersmith.

My question is, if I leave a portion of my extract addition to the very end (last couple mins for sanitation or flameout) will I be able to increase my hop utilization.

I want to make 4-5 gallon batches with a decent IBU level, but can't obtain a large kettle right now. I'm hoping I can get similiar results by playing with hop utilization.

If I add some extract at the end, after the hops have isomerized, then I should be able to attain higher IBU levels than I would if I added all my extract at the beginning. Right?

 

Yes, your hop utilization as it pertains to IBUs will increase somewhat, but a late extract addition is not a substitution for a full wort boil. A full wort boil is the most important thing to do if you want the best hop utilization. If you can't boil 6-7 gallons, then make smaller batches with 3-4 gallon boils and no top off water... or be content with a 5-6 gallons of lesser quality hoppy pale beer w/the top off water. Your choice. I'd rather have 3 gallons of excellent IPA than 6 gallons of mediocre IPA. When all is said and done, you're not only affecting IBUs, since the top off water also dilutes the overall hop character, flavor, complexity, quality. Using 4 oz. more hops to compensate will not solve the issue. It's sort of like salting a steak "after" it is cooked instead of before cooking. You can't compare those as equals and Peter Luger would not be serving you the bland steak that was only salted after cooking.

 

I'll respectfully disagree. Sure, full boils are better, but they also require space, equipment, chilling capacity, etc, etc, that just aren't feasible sometimes. For the longest time I brewed in a townhouse where I would partial mash half the batch, boil 2.5 gallons in my 3 gal pot, then do a late extract addition and dilute up to batch size (5.25 gal) in the fermenter. Now that I've moved I've switched to full boils, but I haven't seen any improvement just due to switching to full boils. Most of my desire was to get into all-grain batches without any extract, not just to boil more water.

There are certainly ways to improve upon some of the smaller boils though. A lot of time they get a bad rap simply because that is what most people start off with, back when we were still following the LHBS instructions like the letter of law and trying to pump out quick batches. You're correct that higher gravity in the boil kettle (like if you added all of the extract at the start) will decrease hop utilization. Adding some of the extract later is an excellent way to bring your boil gravity more into line with the final gravity. Beersmith even has an option to indicate extract as a late addition. I would plan on trying to match the boil gravity to the final gravity. For instance, if you're able to boil 1.6 gal, that's about a third of a 5 gal batch. I'd plan on adding a third of the extract at the start, then the rest right before the end.

Since extract has essentially been boiled once already (when it was made) there's no need to boil it again other than to sterilize it. In fact, boil the entire amount of extract can lead to an increase in color, so a late addition will also help to keep your colors lower for your paler beers. If you're brewing all extract batches, the boil is essentially all about hop additions.

There are a few things to keep in mind when doing late extract additions. First, you want to boil the extract long enough to sterilize it (I generally aimed for 15 min before the end of the boil). When you add the extract, you'll want to pull it of the heat. Both LME and DME have a habit of sinking to the bottom of the pot, where the heat can caramelize or burn them. So pull the pot off the heat, then stir the extract in real well before putting it back to boiling. This is also going to delay the boil a bit while it warms back up. Any additions made before the extract is added will get a little more time in the boil. The 60 min addition isn't much to worry about since 60 min vs 70 min doesn't change much. But if you've got a 15 or 20 min addition, plan on doing the extract before them. You'll especially want to get them in before aroma additions around 5 min or so, otherwise all that aroma will be gone.

Also, double check the recipes first using Beersmith, especially if you do kits from anywhere. If they don't specify a late extract addition, check the IBUs to make sure you're coming out close to the projected number. Late additions actually make using online recipes much easier, because you can assume a similar hop utilization to a full boil recipe.

Finally, not to sound snarky, but don't worry about dilute your hop character. Most of the hop oils are in such low concentration, they never near a point of saturation that we'll have to worry about. The only thing that may happen is that you may reach a level of iso-alpha acid saturation (generally around 100-120 IBU). Does that mean that you won't be able to partial boil an IBU monster like pliny (100+IBUs)? Yeah, at least not easily. But 95% (at least) of your batches will turn out just fine this way, or potentially even better than before.

 

Anything is feasible. Brewers find ways to make things work for them without sacrificing quality. There are many threads on this site that will inform you about unique brewing processes that are not exactly traditional, but produce excellent beers... including the indoor small batch situation you mentioned. I've never had the same recipe under a partial boil come out better or close to the same recipe under a full volume boil... even one with adjustments, extra hops, late extract additions.

 

Cool, for the advice guys. More is welcome if anybody has any.

And yeah, anything is feasible. However, as is true with life (and I'd predict homebrewing as well) sometimes circumstance just doesn't allow for particular possibilities.

 

There is no circumstance that disallows you to brew high quality, award winning beer indoors. Untraditional thinking will allow you to do this even with an electric stove, no top off water, and a few small pots. No excuses really.

 

Did you just read Palmer's book or did you find this info elsewhere? He has a good portion of info in his book about adding extract near flameout. As you said there will be a better utilization of the hops with a lower saturation of sugars in the wort. The key is boiling the DME/LME long enough to still get a hot break and to sterilize it.

 

what about only having access to poor or limited ingredients? If we want to slightly stretch our imagination,we can probablythink of something that would prevent one from making award winning beer. However, I don't really feel like getting into an arguement about whether or not people are limited by circumstance. To argue they are not is asinine. So I'll have to respectfully disagree that people are somehow above environmental influences, be it lack of resources or whatever.

But thank you for your previous advice, it did not fall on deaf ears.

 

No, I haven't read that book. I was just browsing forums for info

 

The gravity of the boil has nothing to do with utilization. BYO experimented with this and the results were confirmed with lab testing of IBUs in the finished batch. What does contribute to utilization as bobbrews already mentioned is the boil volume. The best you can do is 100 IBU of concentration and even that is hard to achieve. If you get your 100 IBU in a 2.5 gallon boil, the best you can get when topped up to 5 gallons is 50 IBU. If you're not trying to brew IPA it wouldn't matter as much.

 

Utilization is a factor of the time and gravity of the boil. A higher concentration of sugars makes it more difficult for the isomerized alpha acids to dissolve.

 

Do you have a link to these results?

 

"...you're not only affecting IBUs, since the top off water also dilutes the overall hop character, flavor, complexity, quality." bobbrews

You know, hadn't thought much about the dilution factor when partial boiling then topping off. That makes total sense to me and believe it's a good argument for dry hopping post fermentation for a few days before bottling. Going to try dry hopping I think, with my next batch which is going to be an extract/specialty grain version SNPA Clone.

 

Diluting wort with top off water does affect the overall hop character, flavor, complexity, quality and aroma too.
That was the main point of my response.

Maybe you should share your vast knowledge of IBUs with bobbrews.

 

I don't need schooling. Yooper was responding to your response, not my statement. I wasn't narrowing down dryhopping with my statement. And I never made a case that dryhopping affects IBUs. Not sure why you focused on the dryhopping aspect.

Nice edit

 

Hey that makes two of us!!
I don't need it either.
I didn't mention IBUs, you did.
Do you get that diluting the wort with top off water will diminish any/all hop character from any/all hop additions prior to topping off?
Again, that was my point.

 

You're confusing me. And I'm not understanding why you're getting so defensive or what I'm being accused of.

Btw, you have perfected this -> http://en.wikipedia.org/wiki/Straw_man

 

Defensive? And what part of my last post are you confused about.

 

http://en.wikipedia.org/wiki/Slippery_slope

 

http://en.wikipedia.org/wiki/Hair-splitting

 

Yoop Yoop!!