To get the actual juice from the tunas, we went through the same steps as we listed in the prickly pear jelly recipe in the Papa’s prickly pear paradise post (before any sugar or pectin are added).
From less than a crate of fruit, we got 10 liters of juice, to which we added 6 cups of sugar (to get 23 brix or 1.095 specific level). We then added 1 packet yeast.
After one week, we siphoned off the bubbling juice into a bottle and added an airlock. After two months total have passed, we will rack it off, making sure there’s no airspace in the bottle. We will then have to rack it off every couple of months until it turns clear.
We have tried it a couple of times, and though the taste is pretty raw (beer-like), it is developing a distinct and interesting flavor. The one true downside though is that you’re supposed to wait a whole year before drinking it.