Big Loss boiling.

[Todes]

Hello, I did some cooking yesterday and everything was Ok but at the end of the boil I had lost so much worth. It was the first time I was using that stove. It brought the worth to boil quick I believe. Is it ok if I turn down the heat a little after the worth is boiling?

thank you.

 

[triethylborane]

I generally boil wort so there is a gentle rolling action, but nothing vigorous. I lose about 1 gallon/60 minutes of boiling. You also have to calculate your grains/ingredients and water usage to account for boil off, trub loss, grain absorption, etc.

Are you doing all grain or extract?

 

[Todes]

I am doing all grain. I put 26L in the kettle, and when there were 20 mins left I had lost more than 4 L

 

[TasunkaWitko]

My experience; your mileage may vary:

After the hot break, a low, gentle boil is fine; no need to go balls to the wall with it.

Also, the wider the pot, the greater the surface area, which means the greater the evaporation.

 

[Todes]

yes, now that you mention it. It is a wider pot. Thank you !!

 

[Biscuits]

From what I understand, the main function of boil-off is kettle diameter...whether you do a simmer or a balls-out boil..you will still boil off essentially the same.

 

[doug293cz]

From what I understand, the main function of boil-off is kettle diameter...whether you do a simmer or a balls-out boil..you will still boil off essentially the same.

The main thing that controls the boil off rate is the actual net heat input to the boil kettle. It takes a specific amount of energy to vaporize a specific amount of water (known as the latent heat of vaporization, which is 2257 kJ/kg or 970.4 BTU/lb.) The net heat input is the total heat input minus the heat lost to surroundings thru conduction, convection, and radiation. The geometry of the kettle will affect the amount of heat lost to the environment, but it is still the amount of heat input that is the primary determinant of boil off rate.

If your boil off is too high, the solution is to reduce the heat input during boiling. Simple as that. The only time you actually know the total heat input into the BK is if you are using an immersed heating element, and are using a power meter. Gas fired, you have know way of knowing how much heat goes into the BK and how much goes up around the sides.

Brew on

 

[madscientist451]

When starting off with a new pot or a different burner/stove, its good to do a boil test. Just put a measured amount of water in your pot, (similar to a batch of beer) boil for 30 minutes, let it cool and measure again. No more guessing about your evaporation rate.

 

[Biscuits]

The main thing that controls the boil off rate is the actual net heat input to the boil kettle. It takes a specific amount of energy to vaporize a specific amount of water (known as the latent heat of vaporization, which is 2257 kJ/kg or 970.4 BTU/lb.) The net heat input is the total heat input minus the heat lost to surroundings thru conduction, convection, and radiation. The geometry of the kettle will affect the amount of heat lost to the environment, but it is still the amount of heat input that is the primary determinant of boil off rate.

If your boil off is too high, the solution is to reduce the heat input during boiling. Simple as that. The only time you actually know the total heat input into the BK is if you are using an immersed heating element, and are using a power meter. Gas fired, you have know way of knowing how much heat goes into the BK and how much goes up around the sides.

Brew on

I love that I can always count on you to give me the nitty-gritty details. The repressed geek in me love you for it.

 

[RM-MN]

Note that what you boiled off is just water. If you boil off so much that you don't have the volume of wort you need into the fermenter, add some back.