effect of the starting boil size?

[omazing]

Hello guys,
I normally brew 6lbs of DME with whatever hops I have. Usually I start with about a 4G of water and go from there. When I cool the wort down and rack it to the fermenter, I usually add about 0.3G of water to bring the wort to 5G before pitching the yeast.

After checking so many recipes online, many of them start with just 2.5G of water and then it calls for another 2.5G of water to be added to the fermenter at the end.

I have two questions:

1) generally speaking, what's the effect of the starting boil size on the batch?

2) lets say I started with 2.5G of water, can I double the usual DME amount (12lbs as opposed to 6lbs) and then split them evenly between two fermenters and add water to each fermenter to bring it to 5G and add yeast to both fermenters to get 2 batches going at the same time?

Thanks.

-Omazing

 

[Cavpilot2000]

Hops utilization is affected by wort density.
The more water you add without increasing the amount of extract proportionally, the more "room" there will be for hops compounds to dissolve in solution.

So let's say you have 5 lb of extract (dissolved solids) in 2.5 gallons of water, using 2 ounces of bittering hops.
If you keep the extract and hops the same, but increase the water, your bitterness will increase.
If you keep the water and hops the same but increase the extract, your bitterness will decrease (the wort is more dense).
If you increase both the water and the extract proportionally, your bitterness should remain roughly the same.

 

[Brownalemikie]

Usually I start with about a 4G of water and go from there. When I cool the wort down and rack it to the fermenter, I usually add about 0.3G of water to bring the wort to 5G before pitching the yeast.

Hmmm, how do you end up with 5 gallons after boiling 4 gallons, then adding 0.3 gallons? Even without the boil you'd have less than 5 gallons.

 

[IslandLizard]

2) Those instructions are for those who don't have a large enough pot or heating source for boiling more volume. Think kitchen stove.

Especially in partial boils one can get much better hop utilization (and better beer) by using only 1/3 of the malt extract at the beginning of the boil, and add the rest at flameout. But there's still a limit to hoppiness in the final beer when only boiling half the volume (or less) and diluting it 1:1 or more. Beers such as IPAs won't come out right that way.

Adding only 1/3 to 1/2 of the malt extract in the boil, adding the balance after flameout, will make better extract beer generally as less caramelization takes place. The malt extract really doesn't need to be boiled, it's ready to go as is.

Now some beers benefit from extended boils and caramelization, such as Scotch Ales and Barleywines.

 

[jurgenph]

what they already said about hop utilization, and...

i think you'll end up with higher SRM, more caramelisation and maillard recations due to the higher concentration of sugars.


J.

 

[omazing]

Hmmm, how do you end up with 5 gallons after boiling 4 gallons, then adding 0.3 gallons? Even without the boil you'd have less than 5 gallons.

Sorry for not being so detailed. I operate from a small kitchen, so to cool the wort I usually dump 2 bags of ice. that usually brings the volume up a bit that's why I don't need to add much to bring it to 5G.

 

[Brownalemikie]

Sorry for not being so detailed. I operate from a small kitchen, so to cool the wort I usually dump 2 bags of ice. that usually brings the volume up a bit that's why I don't need to add much to bring it to 5G.

Aah, ok got it. Btw, good luck with your brew.