Yeah but if you don't hit the required numbers bang on, your volume at the end of the brew day will be more or less & I agree, volumes vary from brew to brew & there's so many factors that can swing it either way on the day. I just add my total volume I've made on the day, punch in the gravity of that collected volume & there's the Brewhouse efficiency. I set my efficiency to 80% & sometimes it's a touch more trub or slightly higher gravity but generally volumes & @80% efficiency are spot on.Birkdale Bob said:Thanks for trying to keep this on track. I read your later post but decided to quote this one. Like you, I use a 40L urn and measure as you do. My concern with using the actual kettle volume to measure efficiency is that if you , for instance, use 80% as your efficiency on the first page of Brew Mate, then you would have to be spot on with the absorption rate and evaporation percentage that you use as a basis for your recipe. I don't think that you can predict absorption rate, it depends on the grain that you are using and the temperatures you have mashed at, and how good your squeeze technique is, plus mashout. I know that some days I seem to get a better boil than on other days, so that is another factor. I am happy to use volume into cube rather than volume in kettle to calculate my efficiency.
I'm a tad baffled just how BrewMate calculates the values & I have been trying to contact Rob for input to this discussion but can't seem to track him down.
I'm not 100% sure how it works it out but every time I brew & set my recipe up @80% eff, 23lt batch, I get 20lt into my cube & 3lt to trub after cooling loss so the trub inclusion plays some part in that total batch size. If I was to set the recipe up for 20lt batch size ( into fermenter / cube volume ) I can almost guarantee that my volume into the fermenter / cube will fall short the exact amount I have my trub set to.
I've brewed with BeerSmith & Beer Tools Pro & set my recipes up so that trub excluded, I get 20lt into my cube but BrewMate is different & the calculation is not the same as some of the other software out there.