I've never used that. Usually they will tell you how much fresh fruit the can is equal to. OR there is a recipe on the can itself. Depending on where you buy it - there is often a place to ask questions about the product on the company website.
Rhubarb wine is one of my favorites. I have about 5 gallons almost ready to bottle. Here's a collection of recipes when you find out how much fresh/frozen rhubarb equals 1 can.
You have two basic ways to run this as an unknown:
* First method would be to measure the TA (example a 4 to 1 concentrate might be 6% acid as Tartaric). Next for 0.70% TA wine (a full body) divide six percent by point seven percent to say you dilute roughly one to eight point five to get a target acidic flavor. This is the preferred method.
* Second option would be to measure the gravity (example a 4 to 1 concentrate might be 1.800 gravity). Subtract one from the reading and then divide point eight by point two to calculate the dilution to get back to a normal rhubarb gravity. From there run it as a normal rhubarb juice.
* I add sugar to make 1.090 gravity in the must and Fermaid O for nutrition. Rhubarb is fairly low pectin so I don’t bother with pectase (but it doesn’t hurt if you add some). Rhubarb is fairly acidic pH so I do not add acid. I like pink color so I add about 100 grams of raspberry (two oz) in a seven gallon carboy.
some fresh rhubarb juice numbers for a target, gravity above assumed a 1.020 since math is easy.
2020 . , , , 1.44% TA , , 1.018 gravity
2019 , , , , 1.38%TA , , 1.018 gravity
2018 , , , , 1.62%TA , , 1.020 gravity , , 3.14pH
late pick , ,1.61%TA , , 1.020 gravity
2016 , , , , 3.31 pH , , , 1.020 gravity