Throwing away the rind and core of pineapples always bums me out. There's still so much pineapple in them. This soda takes advantage of that, plus a dose of brown sugar to bring out some of the same flavors that make pineapple upside down cake wonderful. It's nice in a tall glass of ice with a pretty garnish of mint or, if you really want it to taste like an upside down cake, a maraschino cherry with a bit of syrup from the jar.
Because this soda is lightly fermented with yeast, there's a tee-tiny bit of alcohol byproduct, but mostly its consequence is fizz. Also, because this is a fermentation project, make sure that all of your utensils, pots, and bottles are scrupulously clean.
about 1 quart
Trimmings, rind, and core of 1 pineapple, roughly chopped
Brown Sugar (I like dark, but light would work equally well)
Ginger, grated or finely chopped
Yeast (I like Redstar Premier Cuvee, but other Champagne yeasts work well too)
Dump pineapple trimmings, brown sugar, and water in a deep pot. Bring it to a boil and simmer briskly for 1 hour.
Stir in ginger and lemon juice. Let cool to about 85 degrees Fahrenheit. (When I'm too lazy to get out the thermometer, I know it's cool enough when the pot feels just barely warm.)
Strain the mixture into another very clean pot, crock, or bowl. Pitch in your yeast and stir for one full minute with a very clean spoon. You're trying to mix in oxygen here, so don't be shy.
Cover and let rest at room temperature for a day or two.
Use a funnel to pour the soda into one quart bottle or two pint bottles. Leave two inches or so of head space. Depending on your pineapple and how much water evaporated as your brewed, you might need another small bottle for the excess soda.
Close bottles and allow to carbonate at room temperature. Check them every couple of hours, and when they're carbonated pop them in the refrigerator.
If you're using re-purposed plastic bottles, test by squeezing them. When they're firm, they're done. I use glass swing-top bottles and check them by releasing the tops. When they pop, I know they're carbonated. (Most recipes advise that these are dangerous because they could over-carbonate and explode. In three years of brewing sodas, I haven't had this, or anything else particularly scary, happen. But proceed at your own risk?)