Trent
Well-Known Member
- Joined
- 16/6/04
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- 1,258
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Hey guys
Got a strange little problem that I hope someone can help me with. I have recently started doing double batches, today was my second. My first one on my new system had me 2 points shy of my target gravity, but 4L over my target volume. Today, I hit my target gravity, but was again, 4L over volume. I am pretty sure I didnt mess up my volume calcs, so about 60.3L went into the boil kettle, I did a 90 min boil after it finally started (gotta get me a nasa burner, over an hour to reach boil from 65C is a bit much!), it was a rolling boil, and I syphoned out to my fermenter, took 4L for priming with when I am bottling, then got 47L into the fermenter, and 3.2L left with the trub in the kettle. I know, because in an effort to find out my evap rate, and solve this bloody puzzle, I pulled it all out with a measuring jug (too much hop trub to siphon :huh. So, that is 60.3 - 54.2 over 1.5 hrs, is about 6.6% evap per hour. I know that most people aim for 10-15% per hour, and in the same boil kettle for my 23L batches, I consistently got about 10% per hour. It is an old 18 gallon keg, legally acquired, and the opening is about 25cm in diameter. I boil with the lid completely off. Basically, at the end of the day, it makes no difference to me, and I can allow for such a little evaporation, but I am worried that the volatile compunds that need to be boiled off may not be making their way out, so I am more than anything concerned for the long term flavour and stability of my beers. I am using a 3 ring burner with a normal bbq type reg, and it seems to struggle, if I had a bigger burner, would I achieve my usual 10% evap, or should I just adjust my calculations to suit 6.6%/hour?
Thanks for any advice
All the best
Trent
Got a strange little problem that I hope someone can help me with. I have recently started doing double batches, today was my second. My first one on my new system had me 2 points shy of my target gravity, but 4L over my target volume. Today, I hit my target gravity, but was again, 4L over volume. I am pretty sure I didnt mess up my volume calcs, so about 60.3L went into the boil kettle, I did a 90 min boil after it finally started (gotta get me a nasa burner, over an hour to reach boil from 65C is a bit much!), it was a rolling boil, and I syphoned out to my fermenter, took 4L for priming with when I am bottling, then got 47L into the fermenter, and 3.2L left with the trub in the kettle. I know, because in an effort to find out my evap rate, and solve this bloody puzzle, I pulled it all out with a measuring jug (too much hop trub to siphon :huh. So, that is 60.3 - 54.2 over 1.5 hrs, is about 6.6% evap per hour. I know that most people aim for 10-15% per hour, and in the same boil kettle for my 23L batches, I consistently got about 10% per hour. It is an old 18 gallon keg, legally acquired, and the opening is about 25cm in diameter. I boil with the lid completely off. Basically, at the end of the day, it makes no difference to me, and I can allow for such a little evaporation, but I am worried that the volatile compunds that need to be boiled off may not be making their way out, so I am more than anything concerned for the long term flavour and stability of my beers. I am using a 3 ring burner with a normal bbq type reg, and it seems to struggle, if I had a bigger burner, would I achieve my usual 10% evap, or should I just adjust my calculations to suit 6.6%/hour?
Thanks for any advice
All the best
Trent