Boil Size

[fatcat660]

OK so here is my question. I brew with a small boil of 2 gallons or so. I add 1 gallon of very cold water to the carboy then pour in the wort and top off with more very cold water. This brings my temp down very fast and gives a great cold break. I transfer into a secondary after a week depending on fermentation and keep it there until bottling. I do not have a chiller and my question is this. Does the full five gallon boil give a definitive advantage over having a great cold break and extremly quick cooling to pitching temps.

[Spelt]

Well completely different beer for one. A two gallon boil for everything fermentable is quite concentrated. This will change the melanoidin production and therefore the flavor profile. Despite previous commentary I do believe this will also impact your ability to extract the same amount of alpha acid into the brew so the bitterness changes. Concentrated liquids have elevated boiling temperatures so this may come into play as well when considering the interactions between the amino acids and the tannins in the brew kettle.

Finally you have to boil (to ensure sterility) and then cool down all the diluent water and that is just as much work if not more. Just easier to boil the full wort.

My experience was that the quality of my beers improved dramatically when I moved from 3 gallon boils to 6.5 gallon boils. This being the only change in my process. I feel that even the clarity improved, perhaps because the boil allowed the minerals in my tap water to interact with other elements in the brew pot.

For me, the full wort boil is well worth a few extra grams of cold break. And my wort chiller gets it plenty cool, plenty quick. I'd prefer that my cold break stay in the brew kettle and not sit in the carboy with my beer for a week.

Just sayin'

[Adam]

Actually you won't get better hop utilization at all. This is old school brew science, check out more recent studies. FWIW and YMMV and IDEODAA (I don't expect you old dudes to actually agree...)

Hop utilization isn't linear.

[Spelt]

Actually you won't get better hop utilization at all. This is old school brew science, check out more recent studies. FWIW and YMMV and IDEODAA (I don't expect you old dudes to actually agree...)

Hop utilization isn't linear.

Expand. Educate us. Or point us towards something to read.

[Adam]

Listened to the podcasts of the smaller commercial brewers that talk about transition from small batches to large batches. Stated they work on small home brew type systems to get a recipe, then move to the big equipment to scale it. The one thing they've all said is "hop utilization changes with bigger batches. It isn't linear like the other ingredients. We have to use less or more hops than the linear adjustment would indicate for the batch scale. If we used the same hops as the scale would suggest, it wouldn't taste the same."

I wish I had more to go on but I'm listening to other podcasts to see if there is information I can obtain for this. I've heard this in about a half dozen podcasts during interviews.

[spiderwrangler]

Iophon likes to post things in the forums about gravity not mattering, but generally fails to provide links to any research of studies or anything to support his statements. I think we are all open to taking new research into account (or at least I am), but just posting something and not backing it up is not very helpful. The general angle he is coming from (I think) is that it is not gravity (ie sugars) that cause decreased utilization, but rather the break materials that are produced in higher quantities in these worts. This comes from a recent paper:

Jaskula, B., Aerts, G., De Cooman., L. 2010. Potential impact of medium characteristics on the isomerisation of hop a-acids in wort and buffer model systems. Food Chemistry 123:1219–1226.

"3.3. Effect of wort gravity
According to Laws et al. (1972), McMurrough et al. (1986) and Benitez et al. (1997) wort original gravity is an important factor that influences final a-acids utilisation, i.e., a high gravity wort will promote losses of iso-a-acids, resulting in lower beer bitterness. Conversely, Jacobsen, Hage, Krisensen, and Malterud (1989) could not find a negative correlation between hop utilisation and original gravity of the wort.
Our data in Table 4 shows almost no change in the isomerisation yields when wort gravity was increased from 12 to 15.2 P, whereas wort boiling at 22 P did result in a clearly lower isomerisation yields (on a relative basis, 11% lower compared to 12 P wort boiling). On relative basis, in the 22 P experiment, the isomerisation yields of adhumulone and humulone decreased more than that of cohumulone, which can be explained by the higher hydrophobicity of the ad- and n-analogues. In summary, our data point to a clearly negative effect on iso-a-acids yields and, consequently, on final a-acids utilisation, in the case of very-high-gravity wort boiling."

The Jacobsen et al. (1989) paper is the one that I've come across the most that is pointed to as evidence the gravity doesn't affect utilization, however, they only ran trials between 10.5 P and 13.5 P, a very narrow range of not all that high gravities. So in terms of recent scientific studies, there are two studies more recent than the 1989 paper that say gravity matters, and that 1989 paper is the only one that these authors point out as claiming it does not.

This does not eliminate hot break or other materials as being the basis for hop utilization decreases, as hot break would still have been present based on the methods (grain based rather than extract) used in this study, but it does expand beyond into what would generally be considered high gravity brewing.

Palmer's name has been brought up in reference to iophon's 'new science' as saying that it is due to something other than gravity, but don't remember it being addressed on any of the Brew Strong shows. Has anyone else run across this? If so, provide info/link to your support.

Iophon, if you have access to any other studies that have shown any of this, please provide links to the relevant material, or at least a citation I can follow up on.

[iophon]

Iophon likes to post things in the forums about gravity not mattering, but generally fails to provide links to any research of studies or anything to support his statements. I think we are all open to taking new research into account (or at least I am), but just posting something and not backing it up is not very helpful. The general angle he is coming from (I think) is that it is not gravity (ie sugars) that cause decreased utilization, but rather the break materials that are produced in higher quantities in these worts. This comes from a recent paper:......

Firs off Iophon is not a he. Second of "he" is not fond of posting anything in forums - I made a series of posts in a single thread on this one topic, that is all...

Lastly, and this is perhaps most pertinent, simply reading things off the internet does not make them so and reposting with presumed authority without actually testing it, well I find it a bit arrogant myself, don't you?

Try this yourself and you will find, as I have, that hops "utilization" - a horrible word - is not at all associated with gravity. I have done the following: A double batch in which one is full gravity - as in all grains/sugars added at the start of the boil - and one is much lower gravity in which DME is added at the end of the boil. Hops quantities and schedule identical.

No difference, bitterness was the same, hop flavor was the same. Mind you I am not the only one who has done this test and found the results to be in opposition to the idea that gravity effects hops utilization. Go to http://www.basicbrewing.com and find the March 4, 2010 - BYO-BBR Experiment III episode. That experiment did something similar and backed up the finding with actual IBU tests.

Cheers!

Iophon

PS, there really is a TON of "common knowledge" brew science that is, if you try it yourself, either overstated, or just plain wrong.

[Adam]

http://www.realbeer.com/hops/research.html
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While isomerization is limited during a short boil, hop utilization isn’t linear across the boil time. You don’t need 6 times as much hops for a 10 minute boil as compared to a 60 minute boil. Assuming you’re getting about 30% utilization at 60 minutes, you’ll get around 17% at 20 minutes, 14% at 15 minutes, and around 10% at 10 minutes. So you’ll need to approximately double or triple your hops to get an equivalent bitterness. If you’re already calculating your bitterness with software or some other tool, use the same method to make this adjustment.

Source for above quote: http://www.mrmalty.com/late_hopping.htm