I'm trying to determine why we lost so much wort while chilling and transferring to the fermenter.

Had 28 gallon kettle filled to within 1/2 inch of the top. After boiling for one hour we began to transfer it to the fermenter through a chiller and we only ended up with 18 gallons.

After the boil was completed, I was able to measure we lost 2 gallons and after the transfer there was 2 gallons of trub at the kettle bottom.

I know to expect some more loss due to the temperature conversion that occurs during the chilling of the wort but the end result was a loss of 6 more gallons during the cooling stage.

28 gallons to start
- 2 boil off or evaporation
- 2 trub
- 6 cooling
18 in fermenter

Any thoughts on why we lost so much during cooling?

Brewed on 80F day so water was run through hose through 10 gal bucket of ice, then through chiller and out.

Thanks,
Jim

What are the dimensions of your kettle (diameter and height). My early guess is that you probably made a measurement error somewhere. I would only expect to see a gallon to a gallon and a half lost during cooling. How did you measure the 2 gallon loss during boiling? I lose 2 gallons to boiling in my 5 gallon batches, so I would expect your boil loses to be higher in a 28 gallon batch.

Cheers,
Dave

Thanks for the reply. Don't have kettle measurements handy but we have a measuring stick we use to determine volume. I guess its possible I misread the measurement but it's still an awful large quantity to lose.

We've brewed large batches previously but never had 28 gals. Maybe 24-25 and wound up with 18 in the fermenter.

During your boils are they violent, medium or mild? Since we were so close to the top our's was a mild rolling boil with the lid kept off the kettle.

Are you sure its a 28 gallon kettle? Most sold are 26. I usually loose about 3 gallons during a boil in my 15.5 gallon kettle. I would guess more for a 28 gallon especially if its wide. You shouldn't loose anything during cooling. I only loose maybe .5 gallon for trub also. Do you use an immersion chiller or counterflow?
I would double check your measuring stick to start off with. Good luck, let us know what you find!!

jeepguy wrote:You shouldn't loose anything during cooling.

I definitely lose volume to cooling, though it's not considerable. The wort shrinks as it cools down from boiling to pitching temp. I find that I 'lose' about a quart in a 5 gallon batch due to wort shrinkage. I believe that most brewing programs compensate for this. Beersmith does, for sure.

Cheers,
Dave

Does water expand when it gets hot? I thought that happened only during freezing.

Water is pretty unique in that it expands when hot (as would be expected) and contracts when cooled (as would be expected), however when cooled to below about 4 degrees celsius, it begins to expand again.
You could do an experiment and test it for yourself. Check your volume with a dipstick immediately after your next boil. Mark the level of the wort. After cooling to pitching temperature, check the level again. It should be lower, but it won't be by much. Like I said before, I lose about a quart in a 5 or 5 1/2 gallon batch. It definitely ain't much.
The expansion of hot water is also the reason why you must calibrate your hydrometer for temperature.

jeepguy wrote:I usually loose about 3 gallons during a boil in my 15.5 gallon kettle. I would guess more for a 28 gallon especially if its wide. I would double check your measuring stick to start off with. Good luck, let us know what you find!!

I agree 100%. I would expect to see more wort boiled off, even with a mild rolling boil. Definitely check your pot dimensions and your measurements.

Cheers,
Dave

Thanks for the replies guitarlord & jeepguy.

I'll doublecheck the dimensions of the kettle & measuring stick next brew day as the kettle is not in my possesion. I'll let you know in a few weeks.

Jim

I probably do not notice much of the loss because i really never check how much wort i have left. I usually forget to take hydrometer readings too. I keg so its not that big of deal. If i was still bottling i would check that stuff.
I know my beer has a good amount of alcohol because thats usually why i forget to check on brewday!! Too many of the last brewdays taken in!!

Wort shrinks by about 4% from boiling to pitching temperature. The gravity will remain constant, though.

I expect about 12% to 15% evaporation, per hour. My boil lasts 90 minutes, but they are not the violent volcano boils I see from others. They don't really have to be, either. The gravity should increase during the boil. As long as there are lots of bubbles breaking the surface and moving around the kettle, the boil is fine. For those that like the stronger boils, I would expect the evaporation to be more significant.

At 28 gallons, volume shrinkage from cooling should be about 1.1 gallons. At 15% evaporation, you are at a little more than 4 gallons of volume loss. Totaled, 5 or a little more gallons of loss. Add in the trub loss, and the total goes to about 7 gallons. Since you started below the rim of the kettle, you were already below 28 gallons. If you actually had 26 gallons to start, then the losses take you to 19 gallons or a bit less, in line with what you experienced.

I think you had more evaporation than you think. This assumes you did a masterful job of preventing any boilover. It also assumes you have the correct size on your kettle.

Kev