80% Hydration Sourdough: Exact Weights, Starter Maths & Handling
An 80% hydration dough has 80 g of water for every 100 g of flour. Here is how to hit that number precisely, including the flour and water hiding in your starter.
What 80% hydration means
Hydration is a baker's percentage: water weight divided by flour weight, times 100. With 500 g of flour, 80% hydration means 400 g of water (500 × 0.80). In ounces, 17.64 oz of flour takes 14.11 oz of water. Because it is a ratio, it works the same in any unit, as long as you weigh the water rather than measure it by volume.
For many home bakers 80% is on the wet side. Plenty of everyday sourdough recipes sit around 68–75%, so expect a dough that is noticeably stickier and slacker than a beginner loaf.
Does the starter count? Two ways recipes say "80%"
Your starter is part flour, part water. A 100% hydration starter (equal weights of flour and water) is half flour, half water. Some recipes count it, some don't, and the difference is a couple of percentage points:
| Recipe | Flour | Water | Starter (100%) | Salt | True hydration |
|---|---|---|---|---|---|
| A: "80%" ignoring the starter | 500 g | 400 g | 100 g | 10 g | 81.8% |
| B: 80% including the starter | 450 g | 350 g | 100 g | 10 g | 80.0% |
Recipe A: (400 + 50) ÷ (500 + 50) = 450 ÷ 550 = 81.8%. Recipe B: (350 + 50) ÷ (450 + 50) = 400 ÷ 500 = 80.0%. Recipe B makes a 910 g dough (about 32.1 oz), a typical single loaf for a 5–6 quart (roughly 5 litre) Dutch oven.
Hitting exactly 80% with the calculator
The calculator takes water and starter as a percentage of the flour you add, then shows the true hydration with the starter counted. With a 100% hydration starter, the water percentage to enter for a target true hydration is:
water % = target % × (1 + s ÷ 2) − s ÷ 2, where s is the starter percentage.
For a target of 80% with 20% starter: 80 × 1.1 − 10 = 78%. Enter total dough 900 g, water 78%, starter 20%, starter hydration 100%, salt 2%, and you get:
| Ingredient | Grams | Ounces |
|---|---|---|
| Flour | 450 g | 15.87 oz |
| Water | 351 g | 12.38 oz |
| Starter (100% hydration) | 90 g | 3.17 oz |
| Salt | 9 g | 0.32 oz |
| Total | 900 g | 31.75 oz |
Ounces are converted from the gram figures. If you type 31.75 oz into the calculator instead, a couple of lines may differ by 0.01 oz because of rounding.
Check: water 351 + 45 from the starter = 396 g; flour 450 + 45 = 495 g; 396 ÷ 495 = 80.0%. The same formula gives 67% to enter for a true 70%, 72.5% for 75% and 83.5% for 85% (all at 20% starter, 100% hydration starter).
Which flour works at 80%?
Higher-protein flour holds more water and builds a stronger gluten network. In the US that's bread flour; in the UK, strong white bread flour; in Australia, baker's flour or bread flour. All-purpose (US) or plain flour (UK/AU) can make an 80% dough, but it usually feels much slacker, so many bakers start around 72–75% with it. See bread flour vs all-purpose flour for the naming differences. If part of your flour is whole wheat (wholemeal), 80% will feel firmer than it does with white flour, as explained in whole wheat sourdough hydration.
Handling a wet dough
- Hold back some water. Mix with about 90% of the water and add the rest once the dough has some strength (often called bassinage). If the dough already feels very loose, leave it out. The loaf will simply be a little under 80%.
- Use wet hands, not extra flour, when folding. Flour you dust on the bench lowers your hydration slightly and can leave raw streaks.
- Build strength with folds. Three or four sets of stretch-and-folds or coil folds, 30 minutes apart, during the first part of bulk fermentation.
- Watch the dough, not the clock. Look for a domed, jiggly dough with bubbles on the sides and surface. How much it should rise depends on your recipe and temperature.
- A cold final proof in the fridge makes a wet dough firmer and easier to turn out and score.
Cups, if you must
Water is the one ingredient where volume is reasonably reliable: 1 ml of water weighs about 1 g. 400 g of water is about 1.7 US cups (1 US cup = 236.6 ml) or 1.6 Australian metric cups (250 ml). Flour by the cup varies by 20% or more depending on how it's scooped, which is enough to swing hydration by over 10 points, so weigh the flour. Our grams to ounces chart helps if your scale only shows ounces.
Enter your own flour amount, starter and target hydration and the calculator gives exact grams or ounces, plus the true hydration with your starter counted.
Open the free calculatorFAQ
Is 80% hydration considered high for sourdough?
For most home bakers, yes. Many everyday sourdough recipes are around 68–75%, so 80% is on the wetter side. It is still very manageable with strong (bread) flour and a few sets of folds.
Does 80% hydration include the water in the starter?
It depends on the recipe. Some count only the water you add, others include the flour and water inside the starter. With 20% of a 100% hydration starter, the difference is about 2 percentage points. The calculator shows both numbers.
How much water do I need for 500 g flour at 80% hydration?
500 × 0.80 = 400 g of water. If you also add 100 g of 100% hydration starter, the true hydration becomes 450 ÷ 550 = 81.8%. Use 450 g flour and 350 g water with the same starter for exactly 80%.
Can I make 80% hydration sourdough with all-purpose or plain flour?
You can, but lower-protein flour absorbs less water and the dough will feel slacker. Many bakers start nearer 72–75% with all-purpose or plain flour and work up.