DoughPlan

How DoughPlan Calculates Your Dough

DoughPlan does three calculations: it turns your style and number of pizzas into ingredient weights with baker's percentages, it builds a schedule backwards from the time you want to eat, and it works out how much yeast that schedule needs. This page explains each one, where the numbers come from and where they stop being reliable.

1. Ingredients: baker's percentages

Every ingredient is a percentage of the flour weight, with flour at 100% (see baker's percentage for pizza dough for worked examples). A dough at 60% hydration has 60 g of water for every 100 g of flour. Ooni describes hydration the same way: 1,000 g of flour and 600 g of water is a 60% hydration dough.

The planner works out the total dough weight first:

Flour, water, salt, oil and sugar are rounded to 0.1 g in the calculation (the table shows flour and water to the gram). Yeast is rounded to 0.01 g, because the amounts for long fermentations are small.

2. The schedule

The planner starts at the time you want to eat and subtracts each step:

These step lengths are fixed in the current version. If you prefer a longer bulk or a shorter final proof, the yeast amount still follows the total time and the temperatures, but the clock times in the schedule will not match your plan exactly.

3. The yeast model

The reference: Craig Lomen's yeast table

The most cited yeast reference among home pizza makers is the yeast quantity prediction model published by Craig Lomen (TXCraig1) on the pizzamaking.com forum. The version the thread points to as the latest is the table posted on 22 August 2015. It gives the hours until a dough is ready to bake for 17 yeast amounts and 61 temperatures from 35 to 95 °F (1.7 to 35 °C), for instant dry, active dry and fresh yeast. Its author describes how he built it in the same thread: a time curve for 25 °C, a temperature model from published research on yeast growth (Gänzle et al., 1998), and adjustments against results reported by forum members.

The table belongs to its author and we do not reproduce it here. Please read it in the original thread.

Our formula

We fitted our own formula to the cells of that table with 5 hours or more (707 cells), by least squares on the logarithm of the hours. The shorter cells are rounded to whole hours in the table, so they carry little information. The result is:

ln(hours) = 3.65132 - 0.718909 × ln(IDY%) - 0.175137 × T + 0.001058 × T²

where IDY% is instant dry yeast as a percentage of the flour weight and T is the dough temperature in °C. We tried adding more terms, and none improved the fit by more than half a percentage point.

Several temperatures in one schedule

A cold-fermented dough spends time at room temperature, then in the fridge, then at room temperature again. We treat each stage as using up a fraction of the fermentation: a stage of t hours at a temperature where the dough would need h hours in total uses t ÷ h of it. The dough is ready when the fractions add up to 1. Because our formula has a simple shape, the yeast amount that makes them add up to 1 has a direct solution, with no trial and error. Craig proposes the same additive rule for his sourdough model in a sister thread.

One consequence surprises people: in the planner's default 2 day cold schedule (2 hours at 21 °C, 48 hours at 4 °C, 3 hours at 21 °C), the model counts only about 43% of the fermentation as happening in the fridge. The five hours at room temperature do the rest.

How accurate it is

We compared the formula with every cell of the source table. The mean error by fermentation length is:

Total fermentationMean error against the table
Under 5 hours18%
5 to 12 hours6%
12 to 48 hours4%
Over 48 hours3%

That is error against the table, not against your kitchen. The table itself is "a starting point", in its author's words, and real dough varies more than 3 or 4%. Because short fermentations are less precise, the planner warns you when the total is under 5 hours.

The range where it is valid

4. Converting between yeast types

The planner uses the ratios in the source table: active dry = 1.3125 × instant and fresh (cake) yeast = 3.125 × instant. Published recipes use similar ratios:

So the ratios differ by up to about 20% between sources. That is one more reason to watch the dough as well as the clock.

5. Where the style presets come from

Each style fills in defaults you can change. Here is how they compare with the sources:

PresetOur defaultPublished figures
Neapolitan (AVPN style)60% water, 2.8% salt, no oil or sugar, 250 g ballsAVPN: 1 litre of water for 1,600 to 1,800 g of flour (55.6% to 62.5%), 40 to 60 g of salt per litre (2.2% to 3.75%), "never add fat or sugar", balls of 200 to 280 g
Neapolitan for a home oven65% water, 2.8% salt, no oil or sugar, 250 g ballsOoni: Neapolitan "generally sits at around the 60 to 65% mark". Gozney: 58% to 65%. King Arthur's home-oven Neapolitan-style crust uses 73% (170 g water to 232 g flour) and 3.4% salt
New York (12 inch pie)63% water, 3% salt, 4% oil, 2% sugar, 250 g ballsOoni: 65% water, 3.0% salt, 5.0% oil, 1.0% sugar, 380 g balls for 16 inch pizzas. King Arthur: 57% water, 3.3% salt, 3.3% oil, 3.3% sugar, two 13 inch pizzas from 360 g of flour

The New York preset sits between these two recipes: hydration between King Arthur's 57% and Ooni's 65%, Ooni's 3% salt, oil and sugar between the two, and a 250 g ball, within the 215 to 255 g that their ball weights give when scaled by area to 12 inches. If you want to follow one of them exactly, change those fields. The New York guide has the details.

The Neapolitan AVPN preset can be combined with cold fermentation in the planner, but the AVPN regulations describe a room temperature fermentation of 8 to 24 hours. Choose "Room temperature only" if you want to follow them. The Neapolitan yeast guide explains why AVPN uses much less yeast than our model.

6. Known limits

If the planner gave you a result that did not match your dough, we would like to hear about it on the contact page. Tell us the yeast, temperatures and times, and what happened.

Sources