Evaporation, Trube & cooling loss?

[Brian-d]

I am sure there is no clear cut answer. I live in the Denver area at about 6,000 ft in elevation so I think our boil off would be even higher than normal. I use beer smith, and yesterday I brewed a 5 gallon batch of All grain and used 15% as evaporation rate, 3/4 gallon as loss to trube and 4% as cooling loss which are settings I have used previously. Beer Smith said I should have a pre-boil volume of 7.01 gallons with the above variables, but I was left with just a little over 4 gallons of wort in my fermentor which is the first time I was that far off.

Two things were different with this batch: I used a Chillus Convolutus wort chiller from Morebeer instead of an immersion chiller and Blichmann's hopblocker. Both pieces of equipment worked great. Does anyone have any insight as to why I might have lost 3 gallons of wort with a 60 minute boil? Does the vigor of the boil matter much? Thanks very much.

 

[phoenixs4r]

Vigor of boil matters. That's a lot of liquid tho.

 

[CrazedArmadillo]

I lose 20% to boil off during a 60 minute boil (sea level). Looks like you lost 30%, which seems like a ton (assuming of course the pre-boil measurement was accurate...I made this mistake once).

I've only ever used an immersion chiller, so I'm just guessing here, but since you just switched to a counterflow chiller, is it possible for wort to be left behind in the chiller/hoses? losing a whole gallon to dead space in the chiller seems unlikely, but if the hoses are long enough, etc...

 

[bottlebomber]

It's really hard to call... wort density, diameter of kettle, BTUs of burner... my kettle is like a small hot tub and I lose an amazing 2.5 gallons over a 1 hour boil

 

[CrazedArmadillo]

Yeah, kettle dimensions are a big factor. I purposefully chose one that is taller than it is wide, in order to minimize boil-off.

Instead of just guessing/estimating, I actually measured my boil-off rate prior to brewing for the first time with my new kettle. Just fill with 7 gallons water, boil for 60 min. at the same rate you'll use for brewing, then measure how much is left. Of course it's not 100% accurate because you're boiling water instead of sugary wort, but it's pretty darn close. Now I never have to wonder how much I'm going to lose during the boil.

 

[PoppinCaps]

Have you used this kettle before, and had consistent boil-off? I'm near sea level, and get about 1.1gal/hr boiloff in a 15" dia kettle, 0.75gal/hr in a 13" kettle. Pretty much dead on every batch. I'm sure you have seen this before, but boil-off should be a set volume for one setup no matter how much wort is in there, and from feedback I've seen here the average is around 20-23% given a standard 5gal batch, FWIW. Of course it also depends on elevation, where you are certainly on the high end.

Edit: yep, what ^ said.

 

[Brian-d]

I lose 20% to boil off during a 60 minute boil (sea level). Looks like you lost 30%, which seems like a ton (assuming of course the pre-boil measurement was accurate...I made this mistake once).

I've only ever used an immersion chiller, so I'm just guessing here, but since you just switched to a counterflow chiller, is it possible for wort to be left behind in the chiller/hoses? losing a whole gallon to dead space in the chiller seems unlikely, but if the hoses are long enough, etc...

Thanks. I know my pre-boil measurements are right because I'm using a Blickmann 15 gallon pot with a sight glass, but never gave the wort left behind in the counter flow chiller and hose a thought. There is 12 feet of 5/8ths cooper tubing within the chiller and several feet of hose. I think this is my answer since all other variables were pretty much the same. The Counter flow chiller worked so well that I would have a hard time giving it up. I will however have to account for wort loss because of its use or figure a way to get more into my fermenter that is left in chiller and hoses.

Anyone give me a tip on draining remaining wort from counter flow chiller and hoses?

 

[bottlebomber]

You could stick a hose into your kettle through the drain and blow the wort out

 

[matt2778]

When I switched from a 32quart bk to a 60quart my boil off went from just over a gallon to two gallons. I ended up with two four gallon batches of higher abv beer. I'd just disregard the software and add an extra gallon.

 

[delvec28]

I can vouch for a vigorous boil dramatically increasing the evaporation rate.

I have an aluminum pot so I 'seasoned' it by boiling water for an hour pretty vigorously. Started with 8 gallons and ended with a shade over 6.

Then on my first AG batch, I turned the gas down once it reached a rolling boil - after an hour I only boiled off 1 gallon.

I would also consider the weight of hops added. For my last AG batch, I used 4 ounces of hops and was going to siphon from the kettle to my carboy, but the hops absorbed so much wort that I ended up dumping it all in.