A few questions about water volume

[Superkabuto]

I was looking through the recipes and noticed that this IPA had two different water volumes, a "Batch Size" and a "Boil Size". What is the difference between these? Does the boil size mean the volume of the wort that gets boiled on the stove, and the batch size equal the boil size plus the additional water that is added to the fermenter? This is the recipe:

https://www.homebrewtalk.com/f69/tits-up-imperial-ipa-3-time-medalist-2-golds-1-silver-92914/

Also, is there a rule of thumb about the volume of water that is boiled and the overall batch size? If I'm supposed to boil 2.5 gallons for a 5 gallon batch, does this mean I boil 5 gallons for a ten gallon batch, and so on. What if I boiled 1 gallon for a five gallon batch? How would this affect my beer?

Thanks

 

[Chuck_Swillery]

Boil size is the volume of water you start off with and, typically, leads to your batch size volume after evaporation. However, this can differ depending up on how you're brewing. You may only be able to boil 3 gallons of water then will have to add water to the primary to get to 5 gallons. You do not automatically double water volumes - again, it all depends on how much water you can boil to start with.

I guess the way to look at is this: You want to end up with 5 gallons of wort. If you have the ability start off by boiling 6 to 6.5 gallons of water and boil it down to 5 gallons. However, many MANY people just don't have the space to do a full boil and will boil 2 -4 gallons then adjust to 5 gallons by adding water to the primary.

It all depends on how big a brew pot you have and how much you can boil all at once. Either way you'll end up with good beer. There will be some differences in the result but good beer none-the-less.

 

[Superkabuto]

Thanks,

I was just wondering because in this recipe the batch size was larger than the boil size, so I assume the batch size is the volume you get after adding water.

And you bring up another point that I don't really understand. The final batch size is supposed to represent BEFORE or AFTER boiling off? I assume this will make a big difference in a small batch.

 

[mojotele]

And you bring up another point that I don't really understand. The final batch size is supposed to represent BEFORE or AFTER boiling off? I assume this will make a big difference in a small batch.

Neither. The final batch size is the amount you end up with in your fermenter. Let's take some scenarios:

Scenario 1
Boil volume: 6.5 gallons
Batch volume: 5 gallons

Conclusion - Likely what is happening here is the person started with 6.5 gallons then, after boiling and transferring to the fermenter, had 5 gallons. No water added after boil.

Scenario 2
Boil volume: 3 gallons
Batch volume: 5 gallons

Conclusion - The person started out with 3 gallons and ended the boil with maybe 2 gallons. He then added 3 gallons to the fermenter to get 5 gallons.

Scenario 3
Boil volume: 5 gallons
Batch volume: 5 gallons

Conclusion - The person started out with 5 gallons and ended the boil with maybe 4 gallons. He then added 1 gallon to the fermenter to get 5 gallons. Or this person is just a doofus and didn't write up the recipe correctly.

 

[Frodo]

Thanks,

I was just wondering because in this recipe the batch size was larger than the boil size, so I assume the batch size is the volume you get after adding water.

And you bring up another point that I don't really understand. The final batch size is supposed to represent BEFORE or AFTER boiling off? I assume this will make a big difference in a small batch.

AFTER. The batch size is how much is in the fermenter after you've pitched the yeast and you tuck it away for fermenting. So that would also mean AFTER you've topped the fermenter up to whatever volume you're going to ferment if you couldn't boil the whole volume.

 

[whatsleftofyou]

In a nutshell...

Boil size - The volume of liquid you have at the beginning of the boil. This will be higher than the batch size if you're doing a full boil to account for boil off. Some people do "partial boils", which will be less than the batch size, to which they add water at the end. This is typical for those who don't have the kettle space or ability to do a full boil.

Batch size - The volume of liquid you'll have in the fermenter at the end of the day, typically 5 gallons.

Is there a rule of thumb? Sort of. It's always recommended that you do a full boil if possible. If not, do as big of a partial boil as you can. The amount of volume you lose during the boil will vary depending on your system.

How does this affect your beer? I'm assuming that this is extract since I don't know anyone doing partial boil AG. The size of your boil greatly changes your hop utilization. For example you won't get as much out of your hops if you're boiling 2 gallons as opposed to if you boiled 5+. This is obviously very important since you're talking about a IIPA. A partial boil can also affect the color of your beer due to increased caramelization of the sugars in a condensed wort. Both of these can be remedied somewhat using the Extract Late Method here: http://www.byo.com/stories/techniqu...ct-brewing/619-extract-method-to-your-madness

Hope this helps!

 

[axr]

Boil size - The volume of liquid you have at the beginning of the boil. This will be higher than the batch size if you're doing a full boil to account for boil off. Some people do "partial boils", which will be less than the batch size, to which they add water at the end. This is typical for those who don't have the kettle space or ability to do a full boil.

Batch size - The volume of liquid you'll have in the fermenter at the end of the day, typically 5 gallons.

+1 on this

 

[Superkabuto]

This has all been very helpful. Thank you very much