A healthy sourdough starter should usually be like thick pancake batter – thick enough to mound on a spoon, but still soft enough to slowly flow and level out.

Ideal consistency

  • Think “warm peanut butter” or “thick pancake batter” more than pourable cream.
  • Right after feeding, it can feel quite thick or even a little dry; as it ferments it loosens, becomes airy, and more mousse‑like.
  • At peak, it should be full of bubbles, have risen noticeably, and feel thick, airy, and stretchy rather than watery.

What matters more than texture

  • Activity is more important than exact thickness: a good starter rises after feeding, gets bubbly, and then gently falls back down.
  • Many bakers keep a “100% hydration” starter (equal weights flour and water), which usually gives that thick-batter consistency and is easy to maintain.
  • Starters can legitimately range from quite runny to almost dough-like and still make excellent bread if they are bubbly and regularly fed.

If your starter is too runny

  • Increase flour slightly at each feeding (for example, a bit more flour than water) until it thickens to a heavy batter.
  • Check that you are feeding by weight, not volume; equal weights of water and flour are less runny than equal volumes.
  • Make sure it is not sitting somewhere very warm for too long, which can make it over-ferment and break down into a soupy texture.

If your starter is too thick

  • Add a little extra water at feeding time to loosen it so it just falls off the spoon in a slow ribbon.
  • Very stiff, dough-like starters still work, but they ferment more slowly, so you may need longer between feedings.
  • Once you find a consistency you like, keep your flour–water ratio consistent so your recipes stay predictable.

Quick visual checks

  • Looks: Thick batter, bubbly, and risen; no fuzzy mold or strange colors.
  • Smell: Pleasantly sour or yeasty, not rotten or putrid.
  • Feel: Stretchy and airy when stirred, not completely liquid or dry and crumbly.

TL;DR: Aim for thick pancake batter / warm peanut-butter consistency that’s bubbly and rising after feeds; then adjust slightly thicker or thinner to suit your baking style.