What happens if you don't boil all the wort?

[thrasher141]

Hi folks,
I'm trying to challenge the status quo and find ways to save energy (by boiling less quantity of liquid and/or for less time) and water (by not having to use an immersion chiller so much) in the brewing process.

I want to start brewing larger quantities, say 40 gallons instead of 5.
So the idea is this: after mashing I will have 40something gallons of wort - how about just boil a (relatively) small portion of that, say 5 gallons, adding all the hops to that one kettle. Then let it all cool and combine the boiled wort with the other unboiled (or boiled separately for just a short period of time to ensure sanitization?) wort and pitch the yeast.

I've done a bit of research and have heard you can create off flavors - di-methyl sulfide according to this article: http://www.mashspargeboil.com/boiling-the-wort-why-you-need-to-boil/

But has anybody tried this? Is it really that important? Can you really tell the difference in the finished product?

I might have to do a small scale test of this idea to see for myself, but thought I would first consult the wisdom of the HBT community. Thanks!

 

[stratslinger]

The way I see it, you're going to have a couple of potential issues.

First off, DMS is a very real potential, especially working at the kind of volumes you're talking about. If you don't mind the idea of the flavor of cooked corn in your beer, then by all means go for it. You might try a small batch of a pale ale (something that can benefit from lots of flavor and dry hopping, so it won't be a total loss without the 60 minute addition) but just do a 15 minute boil to sanitize, and see how much the DMS flavor comes across. Obviously different grain bills will vary in their DMS contribution - but avoid Pilsner malt at all costs if you're going to try this approach!

The other issue you're going to run into, especially at these kind of ratios, is hop utilization. There's just no way that 5 gallons of wort is going to utilize enough hop acids to make up for its eventual dilution into 40 gallons of wort. Not gonna happen for most beers. Even the big boys who do brew to a higher gravity and then dilute prior to packaging will only dilute by probably 10-20% tops, where you're talking about an 88% dilution. I just don't see it working out for that reason - though I admit that maybe my imagination is a bit limited there. Maybe if you hopped something to the IBU level of an IIPA, you could then dilute it to something on the level of a mild. But you'd be very limited in the IBU range of your final diluted product.

 

[broadbill]

Using non-boiled wort is a no-go. Mash grains are covered with lactobacillus and end up in the runnings. Even at elevated temps of the mash, I don't think you'd be able to get a good yeast fermentation, it would be overrun by the lactobacillus and anything else on those grains.

Which means you are back to boiling the entire volume, at which I would argue you don't gain anything.

With 40 gallons, you are in the big time...no way to "cheap out"

 

[wilserbrewer]

Get some hop oil extract, all the IBU's you need and more! There is also hop extract for flavor and aroma available.

http://www.yakimavalleyhops.com/category_s/1851.htm

http://www.hopunion.com/1018_CO8322Extract.cfm?p4=open

 

[jonrk]

I have been reading Fix's "Principles of Brewing Science" recently. I took a lok at his wort boiling section. He suggests that there are many chemical reactions and proceses that occur during the boil that significantly impact the final flavor. Getting rid of the cooked cabbage flavor of sulfur containing substances is an important step that occurs in the boiling as stratslinger mentioned. I don't think that boiling part of the wort and then added the two components back together will work as easy as it sounds it might.

I do recommend Fix's book if you want to read more about it. I would be interested to hear the results if you give it a shot.

 

[broadbill]

Not to mention, if there was some way that breweries could save themselves equipment, time, and fuel costs by only boiling partial volumes of wort, they'd be doing it.

The fact they invest in full sized boil kettles and spend the time/money to boil full wort volumes tells you there is some to it doing it this way...

 

[thrasher141]

Thanks for your replies and advice. I think you've convinced me to boil all of the wort. But to compromise, I might use a "no chill" system of emptying hot boiled wort into sanitized containers and letting it cool down over a day or two and then pitching yeast. To save the equipment expense, time, water, etc. Mainly the water use is what bums me out about chilling.

Regarding stratslinger's comment about hop utilitization - I was under the impression that the main factor in hop utilization (besides time of boiling the hops) is the gravity of the wort. Why would it matter that you would be putting 10x the amount of hops into one boiling pot (because you'll later be diluting it down with the other unhopped wort)? That question is just out of curiosity at this point since I don't think I'll be doing that anyway.

 

[latium]

Why would it matter that you would be putting 10x the amount of hops into one boiling pot (because you'll later be diluting it down with the other unhopped wort)?

Because you can only dissolve (isomerize, really) so much alpha acid in the wort before it's saturated. It's the same reason why you can only get about 100 IBUs in a beer by boiling with hops, no matter how many hops you add (although you can use hop extract). Think about dissolving sugar into 1 cup of coffee, as much as it will hold, and then mixing that 1 cup of coffee (decanted off the sugar sludge in the bottom of the mug) into more than .5 gallons of unsweetened coffee. Do you think that you'd be able to get the entire batch sweet enough (assuming you like your coffee moderately sweet)?