Last week I picked the last of the grapefruit from the neighbors' yard - with their knowledge/permission. The last of the grapefruit at this house were picked in mid-April. Today I made the last of the grapefruit juice concentrate. I like to keep things simple so all I do is chop the grapefruits in half, pick out the seeds I can easily see and then take the skin off. Then I just put everything but the skin and big seeds in the blender. After everything is a fairly thick sludge - I freeze in 1 cup containers (mostly yogurt cups). After sludge becomes frozen, I slide the juice into plastic bags to save space in the freezer. I have, I think, about 5 gallons of frozen sludge now.
The sludge is good blended about 50/50 with water plus some ice.