Getting To Know My Equipment - Help Needed

[Wardhog]

I was comfortable with my old kit - I knew boiloff rates, deadspace values, strike temperature water, etc. then I went and upgraded. Now I have to figure them all out again.
On the weekend, I boiled 47 litres for 90 minutes and wound up with 33L, which is near enough to a 30% boiloff/1.5hr rate. My question is, how do I calculate the boiloff %age for an hour? It can't be as simple as 2/3 of 30%, can it?

 

[Gulf Brewery]

how do I calculate the boiloff %age for an hour? It can't be as simple as 2/3 of 30%, can it?

Simple answer - yep, close enough

Complex answer - depends on how long to reach boil and any external factors (wind, boilovers etc etc)


Cheers
Pedro

 

[Thirsty Boy]

plugged the numbers into pro-mash and it says 19.8% per hour .... looks close enough to two thirds to me