1 unit sugar
1/2 unit water
Bring to boil together, let stand a minute or two before adding to anything else. It will yield a little more than one unit, but some recipes rely on that inconsistency. Some recipes expect you to throw out the extra, too, but none of them will tell you just what they expect. See Sweetening page.
If you don't have an apple peeler, slice peel while still on fruit into four sections. If the peels are really big, make a slice around the middle to make it eight pieces. Peel them off the fruit. Taking an paring knife, remove the white, spongy substance (called pith) from the inside of the rind itself. Remove as much as you can, but try to be careful not to completely destroy the rind while you're at it. The pith leaves a bitter taste in the liqueur, but the rind's natural oils are very important to the final taste.
After you've squeezed out what you can, discard the solids. Take the
liquid yield you have so far, and pour through a finer filter, to remove
the small solids that escaped the first pass. Do this as many times as
it takes for you to be satisfied that the liquid is reasonably free of
solids. You might also consider using a wine filter system (which uses
positive pressure to force the liquid through thick filter plates) as a
final, very fine filter step. See the Filtration
|For Straining||Cheese cloth
Cotton or canvas fabric
|For Filtering||Linen, canvas or cotton
Glycerine is called for in a number of liqueur recipes as a thickening agent. Chemically, it is glycerol, a colorless, odorless, sweet-tasting substance with a thick, syrupy consistency. It is also useful in preventing sugar crystallization in candy. In liqueurs, it provides a certain texture to the liqueur, making it feel less thin and watery, in an effort to mimic the texture of some commercial liqueurs produced by distillation (glycerine can be produced as a by-product of fermentation). Glycerine is available in standard, vegetable and Kosher forms, ans should be readily available in wine-making supply stores. Many drug stores have glycerine on the shelf, but there is an ominous "not for internal consumption" warning on the boxes. I have been unable (through next-to-no research) to determine just why that would be, but I strongly recommend a chat with the pharmacist before picking it up. My best guess is that large quantities of pure glycerine might be harmful. But do confirm that it hasn't been denatured or otherwise rendered harmful. Normally, glycerine is a perfectly acceptable food additive.
That said, I don't use glycerine myself. It somehow feels like cheating. So anywhere you see glycerine in any of the recipes, remember that it's optional, and won't materially impact the flavor of the liqueur. While glycerine is sweet-tasting, the quantities used are minuscule compared with the granulated sugar you'll be using. So use it or not at your own discretion, but don't worry that it'll ruin the liqueur if you don't.