[abraxas]

I have been thinking that I would like to brew a couple of ten gallon batches on my 5 gallon set up for a number of reasons.  I would make a wort at about double the strength and then dilute in the carboys.  I realize my mash efficiencies will drop accordingly and I will have to make some hop adjustments to reach a similar final beer but what else is going to be effected? 

Should I be adjusting my recipe for reduced (or increased) melanoidin formation during the boil?  Instinctively, I assume I should increase my boil time, is this a good assumption?

[mvktr2]

I would say this is quite possible and I've heard of other people doing it.  I believe the thing to do is put it in brewing software/hopville.com and see how it comes out.  Not really much different from doing a Parti-gyle only less complicated.  It's probably as simple as running the numbers as you're going to brew it then re-running them as it'll be after you top up with water this should show the effect on ibus, srm, etc.  Example:  Brewing a 1.090 bier @ 5 gallons equals two 1.045 brews, plug in the ingredients into the software to get a 1.045 and see what the soft ware says happens to the srm etc.  Greg Daniels wrote an excellent article on parti-gyle that might be of some use, google it.

Schlante,
Phillip

Ps Whoohooo first post!

[euge]

Why not? But expect a lower efficiency of course. It'll be great. I don't see much of a problem at all.

[akr71]

It also seems like a great way to experiment with different yeast or different hops (when dry hopping).

[diybrewing]

I have done this twice and did not like the results either time. I found the issue to be with the melanoidin formation in the pot. But I also know it was a recipe issue too. Both times I was making beers I wanted to start at around 1.070 and so my wort was really high gravity. If you used this technique for making a 1.050 beer it would probably work.
P.S. I do a fair amount of Partigyles and this does work but you are boiling two beers at different times not one pot for two beers. I love making a Berlineer Weisse and the Maltose Falcons champage beer recipe this way.

[skyler]

I suspect you would have greater kettle caramelization and a darker beer - so I would try this with a style where that wouldn't really hurt, like a Scottish ale or a Porter.

[abraxas]

I suspect you would have greater kettle caramelization and a darker beer - so I would try this with a style where that wouldn't really hurt, like a Scottish ale or a Porter.

Actually I am going to try it with two hefe's since I have one almost ready and I will be able to compare it side by side with one brewed full strength.  Also, I have been wanting to compare 3068 with 3868 side by side and I can push through hefe's in my kegerator relatively quickly in the springtime.

I know Maillard reactions are dependent on the length of boil and the intensity of boil, I'm guessing wort gravity will have some effect on this but I am not finding anything right now.  I am sure this is heavily covered since so many people brew and a higher gravity and dilute when they start out.

I am going to up my hops by 25% or so and keep my boil at about 70 minutes for a comparison, then dilute to a similar starting gravity as my control.  It should be interesting.

[Malticulous]

It's a lot like doing a partial boil with extract.  I've done it topping off 4.5 gallons to five so I could use a five gallon carboy. It worked fine.

[1vertical]

Ps Whoohooo first post!

Howdy and welcome...nice to have you here.  Sounds like good advise.
I made a pilsner recently that was over the top in gravity/viscosity O.G. 1.069 ish.
When the fermentation was over and during the lager phase, It was not clearing
like I wanted it to.  I put in polyclar as a clarifier but my technique also involved
the addition of 1.5 gallons of distilled water to reduce the viscosity...and I dry hopped
at the same time....

I put the water and hops into a corny keg and then carbonated the water thorougly
(I had concerns about oxygen from the water tainting the light colored pilsner beer)
Once the water was carbed up well, I transferred the pilsner from its secondary keg
into the tertiary keg containing carbed distilled water and the hop ball (Sterling).  This really
worked well....perhaps somewhat retentive and some
extra work, but good end result.

[santoch]

I agree that the caramelization is a factor so you will want to do it in a beer that melanoidans are expected.
Also, do not underestimate the decrease in hop utilization you will get due to the high gravity boil.

<copied from Norm Pyle's Hops FAQ Page http://realbeer.com/hops/FAQ.html>
 

According to Rager, if the gravity of the boil exceeds 1.050, there is a gravity adjustment (GA) to factor in:

   GA = (BOIL_GRAVITY - 1.050)
           ----------------------
                0.2
otherwise,
   GA = 0

Non-metric Units
IBU  = (OUNCES OF HOPS) * %UTILIZATION * %ALPHA * 7462
       -------------------------------------------------
                 VOLUME(gallons) * (1 + GA)

Assuming that your beer is supposed to end up at 1.050, then the "normal" GA would be 0.
Doing the same recipe as a concentrated boil raises the GA multiplier to 1 + ((1.100 - 1.050)/.2) = 1 + 5.25 = 6.25

in other words, the denominator for the 5 gallon batch goes to
V*6.25 instead of V*1.  So, the extraction in the concetrated boil will produce 1/6.25 the amount of IBUs for the same addition.


Also realize that there is that upper limit to the number of IBUs you can actually get into solution.  It is somewhere around 100 IBUs.  IN a concentrated boil, you will Max out at 100 during the boil, then dilute it to 50, so basically the upper bound for beers using this method is around 50 IBUs, and that's if you compensate for the lower utilization.  You'll need a LOT of hops to make a hoppy pale ale using this method.

HTH-

Steve
North Bend, WA

[nyakavt]

There's a guy at our tailgate that does this with extract, puts 10 gallons of ingredients in a 5 gallon boil.  All his beers have the typical concentrated boil sweetness, tastes like a hint of molasses.  Maillard reactions are increased by increased sugar concentration.  What I suggest for the lighter styles is not to try and do a double batch, but maybe a 1.5X batch (try to stay below some target boil gravity, maybe 1.080?).  Big commercial breweries do this, but I'm not sure what their boil gravity is and where the cutoff lies.  At some point you are going to be able to taste the additional melanoidin development from a concentrated boil, and I can tell you that above 1.100 boil gravity its definitely there.

Efficiency is the other concern, especially if you batch sparge.  Expect at least a 15-20% drop if you go from a 10 lb to 20 lb grist (batch sparging), all else being equal and collecting the same amount of wort.

[Hokerer]

There's a guy at our tailgate that does this with extract,

Know your lot for next season yet?  We had three homebrewers bring about 10 different varieties to the Spring Game tailgate weekend before last.  That sort of thing needs to be expanded upon.

[bluesman]

Big commercial breweries do this, but I'm not sure what their boil gravity is and where the cutoff lies.  At some point you are going to be able to taste the additional melanoidin development from a concentrated boil, and I can tell you that above 1.100 boil gravity its definitely there.

Efficiency is the other concern, especially if you batch sparge.  Expect at least a 15-20% drop if you go from a 10 lb to 20 lb grist (batch sparging), all else being equal and collecting the same amount of wort.

+1

I believe it's a routine practice at some breweries. I have diluted before many times with no ill effects. I would stick to bottled water for dilution.

[Kaiser]

I believe it's a routine practice at some breweries. I have diluted before many times with no ill effects. I would stick to bottled water for dilution.

It is. But the dilution is done after fermentation which means that the gravity is limited by the level of high gravity fermentation "off flavors" that are acceptable. I think for some of the American lagers the fermentation gravity is about 16 Plato.

Kai

[nyakavt]

There's a guy at our tailgate that does this with extract,

Know your lot for next season yet?  We had three homebrewers bring about 10 different varieties to the Spring Game tailgate weekend before last.  That sort of thing needs to be expanded upon.

Lot 4, we usually bring one keg each.  Where are you guys?