From Bitterman’s Field Guide to Bitters and Amari by Mark Bitterman (Andrews McMeel Publishing, 2015)
Makes about 2¼ cups, 4 (5-ounce) bottles or 10 (2-ounce) bottles
1. Finely chop about one-third of the zest. Put the chopped zest and strips of zest and the remaining ingredients in a 32-ounce glass jar. Seal the jar and shake. Set aside for 4 to 5 days, shaking every day. Taste, and if it isn’t strong enough, let it go another couple of days.
2. Hold a gold coffee filter over a large measuring cup or large bowl. Pour the liquid from the jar through the filter. It is not necessary to dump out all of the solid contents; just pour off as much of the liquid as possible. Sometimes it is helpful, if a lot of solids fall into the filter, to turn it so that the liquid is being poured through parts of the filter that are not blocked. Discard the solids and allow the strained liquid to settle for about an hour.
3. Line a small funnel with a double layer of damp cheesecloth and place in the mouth of a dispensing bottle. Slowly pour the bitters into the funnel, leaving behind any small amount that looks cloudy with sediment. Fill all of your bottles, but do not overfill. You will need some room for the dropper in a dropper bottle and about ½ inch of headspace in the top of a dasher bottle. Seal and label the bottles appropriately. Store in a cool, dark place. Keeps indefinitely, but best used within 3 years.