I figure a gallon sized bag will have to be forced shut when it holds 6 pounds..
I might not have wine making down yet to call myself a wine maker,,
but blackberry picking is another story.
My left hand, the picking one is finally healed.
This season, with my brother's help, I picked 210 pounds.
If all else fails,,, use my "big butt on the bathroom scales" method to weigh your fruit or berries in the primary before you add water.
Don't forget to take out the weight of the bucket. It will weigh three pounds or so.