Boil off rate

[LovesIPA]

I do five gallon all-grain batches. I have an 8 gallon kettle and a propane burner. I typically collect 7.2 - 7.4 gallons of wort and then start boiling. After 60 minutes I'm down to 5.4 - 5.5 gallons. I turn the burner down quite a bit once I get a hot break.

I live in Sacramento and its usually in the 90's and sometimes the kettle is in direct sunlight. The humidity is low to very low.

Does this fall in line with what others are seeing? For some reason I feel like I'm boiling off too much.

 

[Gear101]

The type of pot you have can make the different, taller pot will boil off less. The wide short pots, even the good ones, will boil off a lot more.

 

[cosmatics]

Yeah I'm similar to you LoveIPA, I shoot to get about 5.5 post boil. I use a 13 gallon boilermaker with a 5500 W element, so I boil around 1.5 gallons a hour. I think when I do 10 gal batches that number should go down due more wort with same electric input.

 

[tooldudetool]

I also have a wide 10 gallon pot, which boils off a good 1.5-2 gallons in an hour. It's just one of those things you have to compensate for on your particular system. Don't worry, it's normal. I used to worry about it too, but now I just compensate, plus it shows that you have a nice strong boil, which is a good thing.

 

[Grannyknot]

I have a 15 gal megapot. I usually account for 15% boil off. I can't do a full 10 gal batch due to the fact that I have to start with around 13.5 gal, which leads to a boilover every time.

 

[C-Rider]

Yeah I'm similar to you LoveIPA, I shoot to get about 5.5 post boil. I use a 13 gallon boilermaker with a 5500 W element, so I boil around 1.5 gallons a hour. I think when I do 10 gal batches that number should go down due more wort with same electric input.

As I understand it boil off rate is determined by pot diameter and heat. If you add more liquid and boil for the same 60 min there should be no change in boil off amt.

 

[passedpawn]

I do five gallon all-grain batches. I have an 8 gallon kettle and a propane burner. I typically collect 7.2 - 7.4 gallons of wort and then start boiling. After 60 minutes I'm down to 5.4 - 5.5 gallons. I turn the burner down quite a bit once I get a hot break.

I live in Sacramento and its usually in the 90's and sometimes the kettle is in direct sunlight. The humidity is low to very low.

Does this fall in line with what others are seeing? For some reason I feel like I'm boiling off too much.

That's a lot of boil off, but it is what it is.

If your question is "is it normal", I'd say it falls within believable.

 

[dracus]

I have a 15 gal megapot. I usually account for 15% boil off. I can't do a full 10 gal batch due to the fact that I have to start with around 13.5 gal, which leads to a boilover every time.

What?

I boil 10 gallon batches every weekend in my keggle which is 15.5 gallons. I typically start with 13 - 14 gallons. I've never once had a boil over. They are simple to avoid.

You just need to pay attention, and watch the temperature. As soon as the temp hits 200 degrees you need to be there with the squirt bottle of starsan. Once the boil starts turn the temp down a bit, and stir stir until the foam subsides and then start your boil timer. If it starts to boil over use the spray bottle.

If you do have issues, you can use 5 star defoamer or fermcap, I only use it for starters and if I need to do a 90 minute boil since my volume is higher

 

[Channel66]

What?

I boil 10 gallon batches every weekend in my keggle which is 15.5 gallons. I typically start with 13 - 14 gallons. I've never once had a boil over. They are simple to avoid.

You just need to pay attention, and watch the temperature. As soon as the temp hits 200 degrees you need to be there with the squirt bottle of starsan. Once the boil starts turn the temp down a bit, and stir stir until the foam subsides and then start your boil timer. If it starts to boil over use the spray bottle.

If you do have issues, you can use 5 star defoamer or fermcap, I only use it for starters and if I need to do a 90 minute boil since my volume is higher

Why are you using star san to knock down the boil? Trust me nothing that is in your water will survive being sprayed into boiling wort

 

[Grannyknot]

What?

I boil 10 gallon batches every weekend in my keggle which is 15.5 gallons. I typically start with 13 - 14 gallons. I've never once had a boil over. They are simple to avoid.

You just need to pay attention, and watch the temperature. As soon as the temp hits 200 degrees you need to be there with the squirt bottle of starsan. Once the boil starts turn the temp down a bit, and stir stir until the foam subsides and then start your boil timer. If it starts to boil over use the spray bottle.

If you do have issues, you can use 5 star defoamer or fermcap, I only use it for starters and if I need to do a 90 minute boil since my volume is higher

Good for you.

Your keggle is probably a lot taller, with less surface area than my 15 gallon megapot, therefore it has a lot less boil-off.

I've done 20+ 10 gallon batches on my megapot. I know my system well. If I have 13.5 gallons of ~160 degree wort in it, by the time it reaches 212*, with the swelling, it is too close to the top of my pot, and with a good rolling boil, I will loose some over the sides, especially during hop additions.

With the trub loss at the bottom of the kettle, the most I can get into my fermenters is 9.25 gallons.

 

[tnlandsailor]

For homebrewing, going by percentages for boil off doesn't really work. With the same pot and same burner you will boil off the same amount if you have 10 gallons or 5 gallons in the pot.

As for boil off rate, 2 gallons per hour is not unreasonable. What you really need is a calibrated sight tube on your kettle so that you can see the boil off rate as you go along. With my converted keg, I get right at 1.5 gallons per hour, or about 1/2 gallon every 20 minutes. I use my sight tube to gage the rate as I go along and make small burner adjustments as necessary.

You want a nice churning/rolling boil, not a simmer. But you don't want something so vigorous that it will deposit most of your hops on the inside walls of the kettle either. Get the rolling boil that looks right, then time it and maintain the same rolling boil for an hour. That's your boil off rate regardless of what the actual number is. Adjust your recipes around this value and use your sight tube to make sure you hit it each time.

 

[MaxStout]

For homebrewing, going by percentages for boil off doesn't really work. With the same pot and same burner you will boil off the same amount if you have 10 gallons or 5 gallons in the pot.

This. A given amount of heat energy transferred to the water will result in a given amount of vaporization (enthalpy of fusion). Once you empirically determine the amount of boil off, you can compensate for it next time.

I have a wide 10 gal kettle (16"w, 12"h), and typically lose close to 2 gallons during a 60 minute boil. As others here have mentioned, you just plan for it in your volume calcs.