Adjusting hop schedule for high boil off? Suggestions please? (converted keggle)

[DansBrew]

Hey guys, I'm making my first SMaSH beer tomorrow. Temps are in the 30's in South East PA. I've nailed down my boil-off rate to approx 2.5 gallons per hour(using a converted keg). I plan on a 5 to 5 1/2 gallon final volume. I'm going to need 7.5 gallons into my kettle after sparging. My question is based on my boil off...

If I go into my 60 minute boil with 7.5 gallons and go with my intended hop additions(1 oz@60, 1 oz@10, and 1 oz@ 2) and miss my boil off(based on a mark on my brew paddle for 5.5 gallons) and have to boil longer, what exactly will that do to my IBUs? I'm not worried about the initial 60 minute addition, because I've read that not much utilization takes place after 60. I'm mainly worried about the 10 and 2 minute additions, affecting final flavors...

If I realize that I'm missing that mark by a significant amount, should I just hold off on the 10 and 2 minute additions until im fairly close to that notch on my paddle, then resume the schedule?

Here's the recipe:

10 1/2 lbs. - Vienna malt
1 oz - Centennial @60mins
1 oz - Centennial @10mins
1 oz - Centennial @2mins

Safale US-05 yeast.

OG-1.060 FG-1.015(what brewmasters warehouse says. I'm mashing 150* for 60)
IBU 42, ABV 5.90%

-Thanks for any input!

 

[mrk305]

As you said, I would add the hops with 10 and 2 minutes left in the boil. I usually do a 90 minute boil and add the hops at 60, 15 & 5 and sometimes do a first wart hop also.

 

[skibb]

Yeah when I do 90 minute boils my hop additions usually don't start til 75 or 60 minutes left.

I too brew outside and right now I'm getting 19-20% boil off. To make sure I better hit my numbers I usually overshoot on boil off % so that at the end of the boil I will have my amount or slightly less - then I just top off with water. The impact on IBU's is negligible.

 

[mrk305]

Sometimes, when I end up with too much after the boil I use a 1/2 gallon liquor bottle as a mini fermenter. I ferment in buckets, so it is fun to watch. Right now I have two mini's sitting on top of my kegorater as decorations. When I do this I can fill a 5 gallon keg plus maybe a six pack of bottles.

 

[jgourd]

This happened to me recently. I had a 90 min addition and then 10 5 and 0 additions. I collected samples throughout the boil and noticed that my gravity was still low (you get about 3 to 5 points from cooling). So I decided to extend the boil. The 90 min hops stayed for 100 min but as you said, there's not much more bitterness imparted that long anyways (maybe a few IBUs more). I then kept my 10 5 and 0 min additions to 10 5 and 0. When I felt that I had 10 min left in the boil, I added then 10 and so on. No problems. Hit my gravity dead on.

 

[DansBrew]

Thanks for the help guys...

 

[djcrawfo]

Hey, the IBU effect from high boil-off is real. I have a boil off of 6.5 to 7 gallons per hour regardless of batch size and this is with a relatively low boil. If I crank it up, I bet I could boil off 8-9 gallons without dificculty. I made 10 gallons of pillsner urquell clone this year that tastes almost like a IPA.

 

[jgourd]

Hey, the IBU effect from high boil-off is real. I have a boil off of 6.5 to 7 gallons per hour regardless of batch size and this is with a relatively low boil. If I crank it up, I bet I could boil off 8-9 gallons without dificculty. I made 10 gallons of pillsner urquell clone this year that tastes almost like a IPA.

This can't be right. That would be a ridiculously high boil off rate. At the most, I boil off 2.5 gal per hour. It has to be pretty dry, cool and blowing like hell. I typically boil off about 1.7 gal per hour.

 

[Mysticmead]

Hey, the IBU effect from high boil-off is real. I have a boil off of 6.5 to 7 gallons per hour regardless of batch size and this is with a relatively low boil. If I crank it up, I bet I could boil off 8-9 gallons without dificculty. I made 10 gallons of pillsner urquell clone this year that tastes almost like a IPA.

are you using a nuclear reactor to boil your wort? 6.5-7 gallons per hour boil off is insane

 

[djcrawfo]

For my boil I use a 35 gallon commercial Tilt Braiser. The unit is 104000 BTU so it will heat up quickly. Now the thing that gives me the large boil-off is the surface area. It is about 40" by 40" by 12". Relitively shallow but huge surface area. So even with a low boil I get a large amout of evaporation. I didn't believe that it would affect it either until I brought 13-14 gallons of dopplebock down to about 6 during the perscibed 90 minute boil. I have a keggle and a commercial stove in my set up but being able to get up to boil quickly really speeds up my brewing time. Note that I also do not need to have extended boils. If a recipe asks for a 90 minute or more boil, I can basically ignore it. this setup wouldn't work for a 5 gallon batch.

Back to the subject, in Palmer's calculations you can see that gravity is a factor in the f(G) formula that is used to calculate hops utilization. see: f(G) = 1.65 x 0.000125^(Gb - 1) from http://www.howtobrew.com/section1/chapter5-5.html

 

[erikhild59]

For my boil I use a 35 gallon commercial Tilt Braiser. The unit is 104000 BTU so it will heat up quickly. Now the thing that gives me the large boil-off is the surface area. It is about 40" by 40" by 12". Relitively shallow but huge surface area. So even with a low boil I get a large amout of evaporation. I didn't believe that it would affect it either until I brought 13-14 gallons of dopplebock down to about 6 during the perscibed 90 minute boil. I have a keggle and a commercial stove in my set up but being able to get up to boil quickly really speeds up my brewing time. Note that I also do not need to have extended boils. If a recipe asks for a 90 minute or more boil, I can basically ignore it. this setup wouldn't work for a 5 gallon batch.

Back to the subject, in Palmer's calculations you can see that gravity is a factor in the f(G) formula that is used to calculate hops utilization. see: f(G) = 1.65 x 0.000125^(Gb - 1) from http://www.howtobrew.com/section1/chapter5-5.html

Is that a sugaring setup?

 

[djcrawfo]

A sugaring setup. I am not familiar with this term.

 

[erikhild59]

A large shallow pan for boiling off water from sap to make syrup.usually with a drain and a burner beneath I think.

 

[Mysticmead]

he's using a commercial braising pan in his church's kitchen...not exactly what I would use for brewing my beer but hey.. to each their own.. does the church know you're making beer? seems like most would frown on that... at least here in the south they would..

 

[djcrawfo]

The pastors all enjoy beer and I have brewed with all of them.
The pan is unconventional but works really well. Just a big stainless boilpot with monster power.