Gather ingredients:
1 quart (or 1 liter) of apple cider or apple juice (unpasteurized if possible)
1/2 cup (about 120 ml) of starter culture (active sourdough starter or whey from yogurt) or 1 packet yeast
1/2 cup (about 120 ml) of sugar or honey
1–2 tablespoons blackstrap molasses (optional)
1/4 cup (about 60 ml) water (as needed to adjust volume)
1/2 teaspoon salt (optional)
Sanitize equipment:
Clean fermentation vessel, airlock, lid, siphon/tap, and tools
Mix base:
Combine apple cider/juice with sugar (and molasses if using)
Stir until dissolved
Add fermentation starter:
Add starter culture (or yeast)
Stir thoroughly
Ferment:
Cover with airlock or loosely cover with breathable cloth
Keep at 18–24°C (65–75°F)
Ferment until desired tartness/low sweetness (typically 3–14 days)
Monitor:
Release pressure if using a non-airlock cover
Check taste periodically
Optional “spider eye” carbonation:
Once fermented, bottle with a small amount of sugar (about 1–2 teaspoons per 12 oz / 355 ml bottle) if you want carbonation
Cap tightly
Let bottle-condition at 18–24°C for 1–3 days, then refrigerate
Finish and store:
When ready, transfer to cold storage to slow fermentation
Store refrigerated and consume within a few weeks