I ordered a second of the three-gallon BrewDemon conical fermentation vessels. My original one is amber and is transparent. I received the second one and was a bit bummed to see BrewDemon is now making them out of HDPE-- the same kind of plastic with which milkjugs are made.
Being curious, I decided to verify the volume-markers cast into the side. To be brief, they were not all too accurate.
I looked at this a while and came to the decision to use one can of mr. beer’s 2.87-pound cans of malt in 2.25 gallons of water, which gives a dilution of 1.275 pounds of malt per gallon of wort. The dilution in mr. beer’s LBK is 1.35 pounds per gallon (2.87 pounds divided by 2.125 gallons). 1.275 pounds per gallon is more than my minimum requirement of 1.25 pounds, so the dilution just squeaks by. Using one 1.87-pound can in 1.50 gallons of water delivers a dilution of 1.247 pounds of syrup per gallon-- just barely achieving my minimum.
As an aside, this conical leaves right near 500 cc below the spigot.
I have also found that the stenciled-on markings we see on some company’s 6.5-gallon buckets can also be pretty far from the truth. I understand that the vast majority of brewers here are all-grain, but there are a few of us extract neophytes. To those few, I’d like to suggest that you verify the markings on your vessels. If nothing else, any failures cannot be attributed to volumes and dilutions being erroneous.