Kvások (Sourdough Starter from Scratch)

Method & Lifecycle

1. Day 1 (Initiation): Combine 50 g flour (preferably whole rye or a 50/50 rye and King Arthur blend) with 50 g lukewarm water in a clean jar. Stir thoroughly until no dry pockets remain. Scrape the sides clean, rest the lid loosely on top, and ferment at warm room temperature (24°C–26°C) for 24 hours.

2. Days 2 to 3 (Bacterial Surge): Discard down to 50 g. Stir in 50 g King Arthur Bread Flour and 50 g lukewarm water. Mark height with a rubber band. You may see a temporary burst of erratic bubbling caused by Leuconostoc bacteria; this is normal and will quiet down as acidity builds.

3. Days 4 to 14 (Establishing the Yeast Colony): Continue daily 1:1:1 feedings every 24 hours. Do not attempt to bake bread yet. The culture will smell funky, sour, or like cheese before shifting toward sweet apples and mild vinegar. A reliable rise takes time.

4. Weeks 3 to 4 (True Maturation): Real sourdough requires 3 to 4 weeks of consistent feeding to establish an acid-tolerant yeast matrix (Candida humilis and Lactobacillus sanfranciscensis) strong enough to lift heavy bread dough. Bake only when it reliably doubles or triples in 4 to 6 hours for several days running.

5. Cold Storage & Reviving: Once mature, store in the fridge (3°C–4°C) with weekly feedings. To revive, pull out 24 hours prior to mixing, discard down to 20 g, and perform two consecutive warm 1:2:2 feeds (20 g starter + 40 g flour + 40 g water) to strip excess acidity and restore peak yeast vitality.

Health, Safety & Troubleshooting

• When to Throw It Out (Immediate Dump): Any visible fuzzy mold (white, green, blue, or black) or pink/orange streaks on the starter or jar walls means mold spores or harmful bacteria (Serratia marcescens) have invaded. Toss it, sanitize the jar thoroughly, and start over.

• Looks Bad, But It’s Good (Hooch): A grey, brown, or clear dark liquid layer sitting on top smells strongly of alcohol, acetone, or nail polish remover. This is simply “hooch”—a harmless byproduct signaling the yeast has consumed its food and is hungry. Pour it off (or stir it back in for a sharper sour profile) and feed immediately.

• Overly Acidic / Sluggish Starter: If your starter smells unpleasantly sour, turns runny/watery very fast, or stops rising well, lactic and acetic acids have overrun the yeast. Reset it by using a micro-inoculation: retain only 10 g starter, feed with 50 g flour and 50 g lukewarm water (a 1:5:5 ratio), and repeat for two feedings to rebalance pH.