Full Boil and Hop Schedule

[wulfsburg]

Good Morning everyone,
I am going to attempt my first extract full boil this weekend and wanted to know if someone could link me to a detailed thread, or article outlining how my hop quantity or schedule is going to be affected. I am going to be brewing a light ale, that I would normally put 1 ounce of hops in on a 2.5 gallon boil.

Also, what is the average boil off per hour? Should I start with 6 or 6.5 gallons? I will be using the 40 qt aluminum pot that came with the Turkey Frier I just got for Christmas. (after I prep it of course)


Thanks in advance!!

 

[JJL]

If you want to know how your IBU's are going to change when change boil volumes, it's probably easiest just to use a recipe calculator. This is a free one online. You can tinker around with adjusting boil volumes and ingredients, and it will calculate IBU's, ABV, etc.

As for boil off, it just depends on your set up, temperature, humidity, etc. But, most people use a rule of thumb of 1 gal per hour of boiloff. Your results will likely vary somewhat from this. Personally, I'd go with 6 gal starting boil, assuming you want 5 gal in the fermenter. It's easier to add water to the fermenter to top off if your boil off is lower than expected.

 

[Yooper]

The change in hops utilization would be minimal, so unless the beer was a very low hopped beer I wouldn't worry about the change in utilization. The "new" thinking is that hops utilization is independent of the size of the boil and wort gravity, even though the older calculators still change it when you plug in the numbers.

I boil off about 1 gallon an hour in the summer when it's humid, and closer to 1.5-1.75 gallons per hour this time of year. You can start with 6 gallons or so, and you should be right in the ballpark. You can top off when done if you're short, but you can't take it away if you're over!

 

[neomantra]

The change in hops utilization would be minimal, so unless the beer was a very low hopped beer I wouldn't worry about the change in utilization. The "new" thinking is that hops utilization is independent of the size of the boil and wort gravity, even though the older calculators still change it when you plug in the numbers.

I boil off about 1 gallon an hour in the summer when it's humid, and closer to 1.5-1.75 gallons per hour this time of year. You can start with 6 gallons or so, and you should be right in the ballpark. You can top off when done if you're short, but you can't take it away if you're over!

Yooper, can you point out some references on this? Everything I've ever read or any software I've used suggests much higher IBU per ounce of hops used early in the boil (e.g. 90/60min additions) if you do a full boil compared to a partial. If there is some new evidence to prove otherwise I'd like to read up on how/why that conclusion was made.

 

[Yooper]

Yooper, can you point out some references on this? Everything I've ever read or any software I've used suggests much higher IBU per ounce of hops used early in the boil (e.g. 90/60min additions) if you do a full boil compared to a partial. If there is some new evidence to prove otherwise I'd like to read up on how/why that conclusion was made.

Hmmm, the "newest" old stuff I know if is what John Palmer presented at the 2008 NHC. But if you can't find that, he speaks on Basic Brewing Radio in a podcast called "What is an IBU, really?" and he talks about how his book is incorrect and why he came to that conclusion. Otherwise, some of the notes from the last three NHCs may have some information on that.

He basically says that others' research has shown that IBUs are independent of wort gravity, and only indirectly related to the size of the boil due to the amount of hot break in a kettle.

 

[neomantra]

Ok, the only 2008 NHC palmer presentation I found was on residual alkalinity of water. I looked up the BBR podcast thing and found my way to this thread which I think the OP will also be interested in.

After looking at this stuff I'm not exactly sure whether it matters if you reduce the 60min hop addition. I *think* that in theory you are probably getting 100% utilization even in a 2.5g boil with such a small amount of hops, and so if you left things the same for a full boil it would turn out about the same. Sounds like a different story if you brew an IPA or some other really hoppy kind of beer.