Sourdough Calculator

How to Use the Sourdough Calculator

This calculator provides four essential tools for sourdough bakers. Select the relevant tab and input your measurements to receive instant calculations with detailed explanations.

Hydration Calculator

Hydration refers to the ratio of water to flour in your dough, expressed as a percentage. This measurement profoundly affects texture, crumb structure, and handling characteristics. Enter your flour weight, water weight, and starter details to calculate the overall hydration. The calculator accounts for water and flour present in your starter, providing an accurate total hydration percentage.

Recipe Scaling

When you need to bake more or fewer loaves, this tool maintains perfect ingredient ratios whilst adjusting quantities. Input your current recipe amounts and specify your target flour weight. The calculator will provide scaled measurements for all ingredients, preserving the original ratios that make your recipe successful.

Baker’s Percentage

Professional bakers express recipes as percentages rather than fixed weights. This system makes recipes infinitely scalable and easier to modify. Flour always equals 100%, and all other ingredients are expressed as percentages of the flour weight. This calculator converts your weight-based recipe into baker’s percentages.

Starter Feeding

Maintaining a healthy sourdough starter requires regular feeding with specific ratios of flour and water. The feeding ratio indicates how much flour and water to add relative to your existing starter. A 1:4:4 ratio means for every 1 part starter, you add 4 parts flour and 4 parts water. Higher ratios extend the time between feedings and create a more balanced flavour profile.

Sourdough Hydration Levels

Hydration percentage directly influences dough behaviour and final bread characteristics. Lower hydration doughs are firmer and easier to shape, whilst higher hydration creates more open crumb structures with larger air pockets.

Baker’s Percentage Explained

Baker’s percentage is the professional standard for expressing bread recipes. This system provides remarkable flexibility and precision, allowing bakers to scale recipes infinitely whilst maintaining consistent results.

How It Works

Flour always represents 100% in baker’s percentage. All other ingredients are calculated as percentages of the total flour weight. If you have multiple types of flour, they sum to 100%.

For example, if your recipe contains 500g flour and 350g water, the water percentage is calculated as: (350 ÷ 500) × 100 = 70%

Standard Sourdough Formula

• Flour: 100%
• Water: 70-75%
• Starter: 15-20%
• Salt: 2%

Once you express a recipe in baker’s percentages, you can produce any quantity by deciding your total flour weight first, then calculating all other ingredients from that base number. This makes recipe development and modification substantially simpler.

Starter Feeding Ratios

Your sourdough starter is a living culture requiring regular feeding to remain active and healthy. The feeding ratio determines how much flour and water you provide relative to the existing starter amount.

Common Feeding Ratios

Feeding ratios follow the format starter:flour:water. A 1:4:4 ratio means 1 part starter receives 4 parts flour and 4 parts water.

• 1:1:1 – Daily feeding for starters kept at room temperature. Peaks quickly within 4-6 hours.
• 1:2:2 – Suitable for twice-daily feeding. Provides adequate food for 8-12 hours.
• 1:4:4 – Recommended ratio for most home bakers. Peaks in 8-12 hours, allowing once-daily feeding.
• 1:5:5 or higher – Extended feeding intervals. Useful when you need slower fermentation or before refrigeration.

Signs of a Healthy Starter

A properly fed starter should double in volume within 4-12 hours depending on temperature and feeding ratio. It will have a pleasant, slightly tangy aroma and show numerous bubbles throughout. The surface may dome slightly at peak activity. If your starter develops an acetone smell, separates with liquid on top, or fails to rise, adjust your feeding schedule or ratio.

Temperature and Fermentation

Temperature significantly affects fermentation speed in sourdough. Warmer conditions accelerate yeast and bacterial activity, whilst cooler temperatures slow fermentation and develop more complex flavours.

Optimal Temperature Ranges

• 20-22°C: Slow fermentation, excellent flavour development. Ideal for overnight proves.
• 24-26°C: Standard fermentation speed. Most recipes are developed for this range.
• 27-29°C: Faster fermentation. Monitor dough closely to prevent overproving.
• Above 30°C: Very rapid fermentation. Risk of overproving and excessive acidity.

If your kitchen is cool, fermentation will take longer than recipe times suggest. Conversely, warm kitchens speed up the process. Observe dough behaviour rather than relying solely on timing. Properly proved dough will have increased in volume by 20-50%, feel airy, and show a smooth, domed surface.

Common Sourdough Problems

Dense, Heavy Bread

Several factors contribute to dense sourdough. Insufficient fermentation is the most common cause – the dough needs adequate time for the starter to create gas and develop structure. Weak starter activity, inadequate gluten development through stretching and folding, or too much whole grain flour can also produce dense results. Check that your starter doubles within 4-8 hours after feeding before using it in bread.

Overly Sour Flavour

Excessive sourness typically results from overfermentation or high temperatures. Long fermentation periods and warm environments favour acid-producing bacteria over yeast. To reduce sourness, shorten bulk fermentation time, reduce the starter percentage in your recipe to 10-15%, or ferment at cooler temperatures around 20-22°C.

Flat, Spreading Loaves

Dough that spreads rather than rising upward lacks sufficient strength. This occurs when dough is overproofed, has too high hydration for your skill level, or hasn’t received adequate strengthening through folds. Reduce hydration by 5%, perform more stretch-and-fold sessions during bulk fermentation, and watch for signs of overproving such as excessive doming or a wobbly, loose texture.

Gummy Crumb

A gummy, underbaked interior suggests insufficient baking time or slicing too early. Sourdough requires thorough baking – internal temperature should reach 96-99°C. The crust should be deeply coloured and sound hollow when tapped on the bottom. After baking, resist slicing for at least 4 hours to allow the crumb structure to set properly.

Flour Types for Sourdough

Different flours produce distinct textures, flavours, and handling characteristics in sourdough. White flour creates light, airy loaves, whilst whole grain flours add nutrition, flavour complexity, and darker colour.

Strong White Bread Flour

This forms the foundation of most sourdough recipes. High protein content (typically 11-13%) develops strong gluten networks that trap fermentation gases effectively. White flour produces tall loaves with open crumb structures and mild flavour. For beginners, start with 100% strong white flour before experimenting with additions.

Wholemeal Flour

Ground from the entire wheat kernel, wholemeal flour contains bran and germ alongside the endosperm. This provides substantially more fibre, minerals, and B vitamins. Wholemeal flour absorbs more water than white flour, so increase hydration by 5-10% when substituting. Bran particles can cut gluten strands, so limit wholemeal to 20-30% of total flour for lighter texture, or use up to 100% for dense, hearty loaves.

Rye Flour

Rye creates dense, moist bread with earthy, slightly sweet flavour. It contains less gluten than wheat but abundant pentosans that absorb large amounts of water. Even small percentages (10-20%) add flavour complexity and extend bread shelf life. Higher rye percentages require adapted techniques as the dough behaves very differently from wheat-based doughs.

Spelt Flour

An ancient wheat variety with nutty, slightly sweet flavour. Spelt gluten is more fragile than modern wheat, so these doughs require gentle handling and shorter fermentation. Reduce mixing time and handle minimally to prevent the dough from becoming slack and sticky.

Frequently Asked Questions

How do I know when my dough is properly proved?

Bulk fermentation is complete when dough has increased 20-50% in volume, shows a smooth, domed surface, and contains visible bubbles throughout. For the poke test, gently press a floured finger into the dough – it should slowly spring back halfway, leaving a slight indentation. If it springs back immediately, continue fermenting. If the indentation remains, you may be approaching overproving.

Can I use instant yeast in sourdough recipes?

Whilst possible, adding commercial yeast defeats the purpose of sourdough baking. The extended fermentation time with natural starter develops complex flavours and makes bread more digestible. If time is limited, increase your starter percentage to 25-30% rather than adding instant yeast. This speeds fermentation whilst preserving sourdough character.

Why does my sourdough starter need discarding before feeding?

Removing a portion of starter before feeding prevents accumulation of waste products and maintains a manageable quantity. Without discarding, you would quickly have enormous amounts of starter. The discard isn’t waste – use it in pancakes, crumpets, crackers, or other recipes. Alternatively, feed your starter with a higher ratio (1:5:5 or more) to reduce discard frequency.

How long does sourdough bread stay fresh?

Properly stored sourdough remains fresh substantially longer than commercial bread. At room temperature, cut side down on a board or in a bread bag, expect 3-5 days. The naturally acidic environment inhibits mould growth. For longer storage, slice and freeze for up to 3 months. Toast slices directly from frozen or thaw at room temperature.

What’s the best way to store sourdough starter?

For daily baking, keep starter at room temperature with daily feedings at a 1:1:1 or 1:2:2 ratio. For weekly baking, store in the fridge and feed weekly with a 1:5:5 ratio. Before using refrigerated starter, remove it 12-24 hours in advance, feed it, and let it reach peak activity at room temperature. For extended storage, spread starter thinly on baking paper, dry completely, then crumble and store in an airtight container. Dried starter keeps for months and rehydrates when mixed with equal parts flour and water.