Boil Volume Question

[azguy]

Hi Guys,

Newbie here ... forgive me if this is an old subject.

I have been using Northern Brewer extract kits for my home brews. I have question that maybe you guys can answer ...

The brew kits I use are for 5 gallon batches. The instructions always state to start with 2.5 gallons of water and proceed to the end of the boil with addition of grains, extracts, hops, etc.

I purchased a 10 gallon boil pot because got tired of boil overs in my old small pot. Since it is 10 gallons, I figured ... what the hell. Lets just make the boil volume a full 5 gallons. I then follow the extract recipe as before. At the end, the volume is less than 5 gallons due to evaporation, so I had water to get the final volume to 5 gallons.

My question ... what, if any, is the net effect of having a 5 gallon boil volume vs. a 2.5 gallon boil volume ... following the instructions in the brew kit. Does this change anything? Should I be just boiling 2.5 gallons per the brew kit instructions and adding water after to boil to bring it up to 5 gallons?

Thanks,

Steve

 

[Pantherjon]

Mainly I think it is a time thing...It takes that much longer to bring 5 gallons to boil then 2.5...Also, it plays in part with your cold crashing of the wort..Get it down close to your target pitching temp them add the 3 gallons of cold water to bring it down the rest, it also helps in aerating the wort so your yeast has oxygen when you toss it...

So, yeah, stick with the directions...You will still make beer-probably as well as if you did follow the directions- but, will just take you a little longer..

 

[Gavin C]

Hi Guys,

Newbie here ... forgive me if this is an old subject.

I have been using Northern Brewer extract kits for my home brews. I have question that maybe you guys can answer ...

The brew kits I use are for 5 gallon batches. The instructions always state to start with 2.5 gallons of water and proceed to the end of the boil with addition of grains, extracts, hops, etc.

I purchased a 10 gallon boil pot because got tired of boil overs in my old small pot. Since it is 10 gallons, I figured ... what the hell. Lets just make the boil volume a full 5 gallons. I then follow the extract recipe as before. At the end, the volume is less than 5 gallons due to evaporation, so I had water to get the final volume to 5 gallons.

My question ... what, if any, is the net effect of having a 5 gallon boil volume vs. a 2.5 gallon boil volume ... following the instructions in the brew kit. Does this change anything? Should I be just boiling 2.5 gallons per the brew kit instructions and adding water after to boil to bring it up to 5 gallons?

Thanks,

Steve

With a greater boil volume the wort has a lower gravity. I think that results or can result in better isomerization of alpha acids in the hops.

In short, you'll need less hops with a full boil than a partial boil if targeting the same IBU's for both brews.

Full boils are generally considered to result in better beer. A very subjective concept so I'm sure many will disaggree.

As a side note.



You have a 10 gallon pot and a burner capable of bringing 5+ gallons to a boil.

If the burner can bring 7 gallons to a boil there is nothing to stop you from doing 5 to 6 gallon BIAB batches. I'm just throwing the idea out there for your consideration. A big pot and strong burner are two equipment hurdles to going all-grain.

next extract batch do a full boil allowing for boil off. Start with ~6 gallons and see where you are at the end of the boil.

If you can measure volume accurately this will tell you your hourly boil-off. A useful bit of info going forward hower you decide to brew in the future.

Welcome to the forum.

 

[rob_mcd]

If you vary the boil volume of an extract recipe you will affect the hop utilization, resulting in a (potentially large) variation in the bitterness of the resulting beer.

Hop utilization is affected by the gravity of the liquid in which the hops are boiling. Higher gravity yields less bitterness (= less utilization). So by diluting the extract batch at full boil volumes you'll want to adjust the amount of hops you add (you'll add less hops than what the recipe calls for), or make a more bitter beer. This is, mostly, for bittering hops (i.e. those added with 30 or more minutes left in the boil). I'm sure there are probably impacts to aroma additions, but would suspect the impact is much less significant.

I have used the Brewer's Friend IBU calculator to adjust hop additions for extract brews before with success.

 

[ballsy]

Hi Guys,

Newbie here ... forgive me if this is an old subject.

I have been using Northern Brewer extract kits for my home brews. I have question that maybe you guys can answer ...

The brew kits I use are for 5 gallon batches. The instructions always state to start with 2.5 gallons of water and proceed to the end of the boil with addition of grains, extracts, hops, etc.

I purchased a 10 gallon boil pot because got tired of boil overs in my old small pot. Since it is 10 gallons, I figured ... what the hell. Lets just make the boil volume a full 5 gallons. I then follow the extract recipe as before. At the end, the volume is less than 5 gallons due to evaporation, so I had water to get the final volume to 5 gallons.

My question ... what, if any, is the net effect of having a 5 gallon boil volume vs. a 2.5 gallon boil volume ... following the instructions in the brew kit. Does this change anything? Should I be just boiling 2.5 gallons per the brew kit instructions and adding water after to boil to bring it up to 5 gallons?

Thanks,

Steve

They instruct partial boil for ease of use....figuring a large % of people doing it are newer and thus likely not using a big pot capable of full volume boil, &/or doing it indoors on a stove top burner.
When adding all extract of a 5gal kit at beginning of boil in a partial (2.5 gal) volume...you are jacking up the concentration of sugar thus it's gravity reading would be enormously high leading to poor hops isomerization (utilization) and likely less than intended hop bitterness being extracted. You would certainly get better utilization of the hops if adding all extract at beginning by starting with full volume b/c your amount of sugar would be appropriate.
The other option (which is beneficial to the overall final beer when brewing extract) is staying at lower volume and only adding some (like 1/3rd) of the extract at the beginning thus the concentration of sugar is more equal to the volume meaning hops are isomerized more as they should be...and the remainder of the extract is stirred in at flameout followed by topping off with cold water to total volume (which also means less time cooling the wort!).

 

[azguy]

Thanks for the replies, guys.

I think next batch, I will stay with full boil. The loss due to evaporation is running less than one gallon. I think that is because with extract, one adds liquid to the boil. Depending on recipe, but it generally is running for me about 2 to 3 quarts evap loss.

I like the suggestion about shooting for the IBU of the hops. I will give that a try.

Thanks.

Steve

 

[daksin]

Yup, just start with a bit more water next time and you'll be fine. I think a full-boil with extract is the way to go!

 

[azguy]

Yup, just start with a bit more water next time and you'll be fine. I think a full-boil with extract is the way to go!

Thanks for that confirmation. Since acquiring the 10 gallon brew pot, I have been making the brews as a full boil. I start with 5 gallons of water and seep the grains. Then bring to full boil. After adding the dry and liquid extract, the volume rises to about 5.5 gallons. But, during the 60 minute boil, evaporation loss brings the final volume to right at 5 gallons. If it drops below that, I add more water at the end to have a final volume of 5 gallons.

I have seen others recommending that with a full boil, that I might want to reduce the amount of bittering hops. I did not know that before, but not sure I would change that as I like the more bitter taste.

So far, results have been good. Just looking for some guidance on how to make it better. Maybe soon I will go to partial mashing.

Steve

 

[daksin]

Many recipes for extract (particularly the ones on this website), and almost every recipe for partial-mash or all-grain will be for a full-volume boil. Most extract kits, however, are for partial boil, so it won't be forever that you have to deal with the discrepancy. However, for most average-gravity, average IBU beers, the difference in bitterness will be minimal. The only change will be slightly better utilization from the lower gravity wort in a full-volume boil, but I'm not sure that I could even tell the difference in anything below IPA-levels of bitterness.