Drawn to its outside size
For temperature control around a starter jar
Brod & Taylor Sourdough HomeA small heating-and-cooling chamber for a jar, rather than a full dough bowl.
41 to 122°F, heats and cools8 × 10 in outside
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Which water for a sourdough starter?
Ordinary tap water works for most starters. If yours is heavily chlorinated and a new starter is slow, use filtered water or leave tap water out overnight so the chlorine can escape (chloramine does not escape this way; a carbon filter removes it). The water's temperature matters more than its source: King Arthur uses room-temperature water, 68 to 70°F, lukewarm in a chilly house and cool in a hot one.
Usually fine: tap water. Slow new starter and strongly chlorinated water? Filtered water. Biggest lever: lukewarm water in a chilly kitchen, cool water in a hot one (King Arthur).
Tap water
Municipal water is treated with chlorine or chloramine to keep it safe. At the levels in most tap water, an established starter does not notice. A brand-new starter is more delicate, which is why some bakers use filtered water for the first week of making one. Water is not a reason to throw a starter out; fuzzy mold, pink or orange streaks, or a smell that is not its usual clean, sour one are (when to throw a starter out).
What to avoid
Distilled or very soft water is fine for the yeast but gives a slacker dough; softened water from a home salt softener is high in sodium and best avoided. Water that has been boiled and cooled works but is unnecessary. Use water safe to drink.
Temperature matters more
Lukewarm water warms a feed in a cold kitchen, so the starter peaks sooner; King Arthur's starting point is room-temperature water, 68 to 70°F. For dough, the water temperature calculator works out the water needed for dough at 75 to 78°F. Use warm, not hot, water, as King Arthur says when reviving a starter; our own limit is about 100°F.
Questions bakers ask
Does tap water kill sourdough starter?
Almost never. Heavily chlorinated water can slow a new starter; filtered water solves it.
What temperature water should I feed my starter?
Room temperature, 68 to 70°F (King Arthur); lukewarm in a chilly kitchen, cool in a hot one. Warm, never hot: we stay below about 100°F.
Equipment for this job
Keep what you own when it does the job. These are the other exact models we profile.
Drawn to its outside size
OXO Good Grips 11 lb Stainless Steel Food Scale
For seeing the display past a wide bowl
OXO Good Grips 11 lb Stainless Steel Food ScaleA pull-out display helps keep the reading visible under larger containers.
11 lb (5.0 kg), reads in 1 g steps