Ive seen a few threads on here about this but they all get off track of the original question pretty quick. I'd like to hear from someone who has done both about how big of a difference they noticed in the final beer. How much difference in taste is there?
Full vs partial boil
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That's hard to say... I only do partial boils with some extract beers (kits), but..... with extract it seems that a full boil, among other things like late/flameout extract adds, limits caramelization and thus makes a better brew, less 'twang', etc.
As far as the stuff about better utilization in a full boil, I don't buy it. John Palmer has even been talking about how work viscosity has little to do with hops isomerization in the boil. And, IME, I've never gotten 'better' utilization in a full boil, or 'worse' utilization in a partial. I've even done full and partial boils adding ALL the extract at flameout (only steeping grains tea in the boil), and the hops weren't any stronger that any other time.
My suggestion, if you can do full boils, do it. If not, no biggie, just take extra measures to limit extract caramelization.
As far as the stuff about better utilization in a full boil, I don't buy it. John Palmer has even been talking about how work viscosity has little to do with hops isomerization in the boil. And, IME, I've never gotten 'better' utilization in a full boil, or 'worse' utilization in a partial. I've even done full and partial boils adding ALL the extract at flameout (only steeping grains tea in the boil), and the hops weren't any stronger that any other time.
My suggestion, if you can do full boils, do it. If not, no biggie, just take extra measures to limit extract caramelization.
nordeastbrewer77 -- i use beersmith and i notice if i set it to add extract at flameout, the bitterness goes off the charts. but you're saying this hans't been the case in your experience? i get about half my fermentables from a partial mash but have still been adding some extract before the first hop addition because of utilization concerns.
I think the common thought was, and still is that viscosity can influence hops utilization. I always read that, heard that, and believed that. Then a few on here started talking about maybe it doesn't have an affect after all. John Palmer's talked some about this, someone posted a link on an old thread, I'll see if I can find it and post it here.
Anyway, like most folks I started on extract kits (still brew 'em here n there) and did partial boils. When I moved on to AG and PM brews, I got a bigger pot and started doing full boils, even on the extract kits I did. I didn't notice any enhanced bitterness or flavor/aroma from the hops. So, I decided to try a kit I'd brewed a few times as a partial boil and do it in a full boil, no other changes. (this was Midwest's Amarillo Pale Ale). I did a full boil, and when I compared that beer to tasting notes of that beer as a partial boil, I didn't get any difference in bitterness, flavor/aroma or the balance of the beer. I'm not saying I've proven anything, I think the jury's still out until the experts like Palmer and JZ say for sure otherwise, but in my experience, I think the old thinking may change.
One thing I always recommend, and do myself if I have a question or am wondering how something works, is to experiment a lot. Brew the same beer the same way twice, but do one as a partial boil and one as a full boil. You'll know if there's a difference. I do stuff like that anytime I'm wondering how one change will affect a brew, split the batch or brew it twice with that one change. It's a great way to learn about the processes.
Edit: this thread touches on it, and mentions some podcasts. I'm still looking for the link to Palmer's take on it.... I'll find it..... here's the link to the BN podcast on the topic. Here's a thread from another site discussing the BN podcast. Again, I think the jury is still out on this, but.... we may be onto something here.
extra edit: one thing I think helps perpetuate the old thought is that partial boils (with all the extract in boil) of extract beers causes caramelization. That affects fermentability and leaves you with a sweeter, high FG beer, thus less hoppy. A full boil limits kettle caramelization of the extract, thus a more fermentable, lower FG, 'hoppier' brew. So in that sense, I think yes, viscosity can affect hops, but because of caramelization and not because of the gravity of the boiling wort.
With a partial boil the specific gravity of the wort is higher and the solubility of the wort decreases. As a result the hop utilization also decreases, resulting in a less hoppy beer. A full boil has a higher solubility therefore the utilization of the hops increases.
Above and beyond this mindset, decreased hop utilization is definitely still a factor due to the fact that you're diluting the beer with a good deal of top off water.
Example:
Brewer #1 achieves approx. 90 IBUs by boiling 6.0 gallons of wort down to 5.0 gallons, with no top off water. His final beer still retains approx. 90 IBUs in the end.
Brewer #2 achieves approx. 90 IBUs by boiling 3.5 gallons of wort down to 2.5 gallons. Then, the brewer tops off with another 2.5 gallons to reach 5.0 gallons. When he/she does this, the perceived IBUs are cut in half to 45. If you factor the reduced hop utilization concept into this (let's say a mere 20% utilization is lost) then you're left with something more like 36 IBUs in the end. Even if Brewer #2 employed a huge late extract addition and used double the amount of hops to account for the dilution, they will never achieve 90 IBUs... not in their wildest dreams.
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If you want to brew better beer all-around, then do not make a concentrated wort which is later diluted. Two beers, one with a full volume boil vs. one with a partial volume boil of similar recipes will be night and day in terms of quality. Late extract additions will NEVER be a substitute for a full volume boil... no matter what you may hear.
Above and beyond this mindset, decreased hop utilization is definitely still a factor due to the fact that you're diluting the beer with a good deal of top off water.
Example:
Brewer #1 achieves approx. 90 IBUs by boiling 6.0 gallons of wort down to 5.0 gallons, with no top off water. His final beer still retains approx. 90 IBUs in the end.
Brewer #2 achieves approx. 90 IBUs by boiling 3.5 gallons of wort down to 2.5 gallons. Then, the brewer tops off with another 2.5 gallons to reach 5.0 gallons. When he/she does this, the perceived IBUs are cut in half to 45. If you factor the reduced hop utilization concept into this (let's say a mere 20% utilization is lost) then you're left with something more like 36 IBUs in the end. Even if Brewer #2 employed a huge late extract addition and used double the amount of hops to account for the dilution, they will never achieve 90 IBUs... not in their wildest dreams.
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If you want to brew better beer all-around, then do not make a concentrated wort which is later diluted. Two beers, one with a full volume boil vs. one with a partial volume boil of similar recipes will be night and day in terms of quality. Late extract additions will NEVER be a substitute for a full volume boil... no matter what you may hear.
Is this based on experience? Seems to be some conflicting opinions here.
That's a pretty broad conclusion to your argument, which, to me, logically concludes that one cannot exceed 50 ibus with a 1:1 dilution
I didn't really get the point of that either. If you wanna know what/if the differences would be, brew two batches. Even if they're both smaller batches. Do one as a partial and one as a full boil. Stick with a lighter beer and preferably one ya know, and do everything other than boil size/topping up the same way. Carbonate to the same volume of co2. Compare. Nothing can compare with personal experience.
Why would you assume the same amount of hops in 6 gallons gave the same final IBU's as in 3.5 gallons? Maybe if you were trying to get 90-100 which is pretty much the upper limit, and something I would never be considering, but if it is a more realistic example then you should get the same outcome that Nordeast described, which is the same or very similar utilization even with a partial boil.
jvp1
Well-Known Member
Yeah, I don't entirely buy that conclusion, unless you are going for 90 IBUs. It seems to me that were you to use the same amount of hops in a half boil as a full boil, your half would be more concentrated and would dilute with top-off water to about the same as the full boil.
I think that NordeastBrewer77 had it right when he said to do full boils if you can but do half boils if you can't. I think some brewers who consider themselves purists get up in arms about things like this issue (or glass vs. plastic, or what kind of sanitizer to use, or everyone's favourite "to secondary or not to secondary", or classic beer-snobbery) when there really isn't much of a reason to.
I think that NordeastBrewer77 had it right when he said to do full boils if you can but do half boils if you can't. I think some brewers who consider themselves purists get up in arms about things like this issue (or glass vs. plastic, or what kind of sanitizer to use, or everyone's favourite "to secondary or not to secondary", or classic beer-snobbery) when there really isn't much of a reason to.
BobBrews wants me to clarify my post.
IM: " I actually never assumed what you're saying and never made reference to using the same amount of hops... obviously more would be needed. You may want to edit your response in the thread to avoid further confusion."
The topic at hand is how much how much of an effect partial boil is going to have on hop utilization. As Nordeastbrewer77 and others, including myself have noted by personal experience, it does not seem to be a big issue. This is supported by some experts in the links posted above.
If you are trying to get a 90-100 IBU beer like in your example, yes you probably have to do a full or near full boil.
But for most brews, when doing a partial boil, the 3.5 gallons of wort is much more bitter than the full boil 6 gallons so when you dilute you end up with very similar IBU's. Obviously the brewer isn't going to drop the total amount of hops in the recipe because he is doing a partial boil. With most brews, Hop utilization will be slightly less with a partial boil, but no where near the 70% reduction in your example.
I never assumed this. Thank you for clarifying that I never mentioned using the exact same amount of hops for each recipe. Moving on further...you guys are missing basic point. You cannot compare the utilization rate of a full volume boil to a partial volume boil. Therefore, it is not so simple to bitter the partial boil recipe to actual 180 IBUs (if that's even possible) to end up with actual 90 IBUs. Most likely, you'll bitter to about 90 at most and end up with around <45 IBUs. Even if you add the majority of extract late, you are still not achieving anywhere around 90 IBUs.
True again. But again, the example is for a super high IBU beer where the upper limits seem to be about 100 IBU no matter how many hops you add to your boil. But lets take a normal IBU pale ale or stout, if you use the same amount of hops and make the recipe twice with a reasonable partial boil volume and some late extract additions with top off vs full boil with again some late additions of the extract, you are going to get very similarly bittered beers in the end product.
Hop utilization suffers regardless of the beer style under a partial boil. I was just using something like a DIPA as an extreme example, where the importance of a full boil is much more apparent. Nevertheless, a partial boil brewer would be extremely hard-pressed to attain 50 IBUs for any beer style if they initially bittered to 100-90 and then doubled up on top off water. That concentrated 100-90 IBU mark is reduced by at least half... even less with decreased utilization taken into account in a super-concentrated, high OG wort. And as I said before, late additions will redice the amount of decreased hop utilization somewhat, but they are no substitute for a full volume boil.
Really? I've yet to see anything, other than people saying that, that suggest that that's entirely true. Like I said, a partial boil can affect OTHER things, especially with extract, like caramelization. Which then in turn may affect how the hops come through in the beer. Without a lab, I can't prove this, so I'll leave that up tot the experts. But I myself, am thoroughly convinced based on my experience.
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