I brewed this past weekend and another time in February with similar boil off results. I am brewing extract but doing full boils. I put in 6.5 gallons at the start for each batch. By the end of the 60 minute boil my volume is all the way down to 4 gallons (even a little less this past weekend). Anyone have some tips or insight to why this would happen? Even after checking boil off calculators for my kettle size it is off. It is frustrating! Thanks, Tim
Thanks for that bit. I did forget about that piece of info. It probably led to a fair amount of loss. Would you suggest just adding more water? I was going to try for 7.5 gallons this Sunday when I brew again.
Remember if you just add water (without more malt) this will affect the ABV and FG of your finished beer.
Calculators 1) assume your process will evaporate a pre-determined amount of the pre-boil volume and 2) are nothing more than first approximations. Apparently ... your actual evaporation rate > calculated rate ==> more pre-boil volume or a adjusting the flame to achieve a lower evaporation rate to produce the desired batch-size volume is needed. If your post-boil volume was 'x gallons' short into the fermentor ... then try increasing the pre-boil volume by the same amount.
Adding water will change the BU and GU of the wort. If he's only got 4 gallons of wort at the end of a boil, it wouldn't be a bad idea to add another gallon of RO or distilled water before KO. Hops will be off a bit, but not as much as if you only had 4 gal of heavy gravity beer. Gravity points don't boil out. They just increase as volume goes down D/T boil off. Hop isomerization is limited a little when in higher gravity wort. @TJRoar I have a very wide brew pot. (18" In diameter)? I can boil off about 2 gal of volume in an hour. I usually just simmer the wort for 60 min and I get a lot closer to 1 gal per hour. After a few batches, you'll get some consistency with this part of your process.
You can play with your boil rate to help bring your evaporation loss down as well. You really only need a slight boil, just enough to turn the wort over. No need for a rager the entire time. i usually start with a good rolling boil for a few minutes to get a good hot break then calm it down.
I've never used a calculator to estimate boil off rates, but I imagine it would get a hand-waving guess at best. There are too many variables to easily capture in a calculator. I brew outside on a natural gas burner, I notice big differences depending on if I brew in Jan or June. The wind matters a bit as does the batch size. With that said, 6.5 -> 4 gallons seems like a lot for a 1 hour boil. How many hops did you use? Are you sure you started with 6.5 gallons? How strong was your boil, raging or little more than a simmer?
My kettle is 15 inches in diameter and I think 18 inches deep (forget from when I measured last). I brew in my garage on an edleman burner I got from Norther Brewer (big one with copper edges) I put in 6.5 gallons to start and ended right around 4 gallons the past two batched I brewed. The boil was roaring as the burner pumps out some serious heat and brings the water to boil fast. I'm thinking because my last batch I did a 15 minute whirlpool I lost more than in the past. I definitely need to brew more and just fine tune my system and brewing. Of course once I do this with extract and zero in my amounts I will move over to all-grain. But this is all in fun and for the love I have of the brewing process. Thanks for the advice guys!
Yeah, but a lot of your water/wort loss stuff will carry over to all grain, like water Boiloff Rate, Hop wort absorption, Kettle Deadspace (if applicable), and Kettle to Fermenter Hose/Pump/Siphon Loss (if applicable).
I have the same burner and have only used it twice. The first time I had it wide open the whole time and boiled off more than expected, though it wasn't close to 2.5 gallons (think it was 1.5-1.75). The second time, I turned down the throttle and was around 1.25 gallons for a 60 min boil. When it's wide open, I have waves on the surface of 7 gallons of water.
