Sourdough Bread Lab152 recipes

Sourdough Bread Lab

Two styles in 152 sourdough bread recipes

Leave the recipe names aside and group the 152 recipes by their 5 ingredient ratios alone, so that recipes built alike land together. Each group is named only by the numbers: the ingredients where its recipes sit furthest from the middle of all 152.

The data splits best into two groups, and they separate: a silhouette of 0.42, on a scale where 0 is no separation and 1 is complete. They still touch at the edges, so a recipe near a boundary could sit in either.

The recipes on one map

Every recipe, placed on the two directions along which the ratios vary most (a principal component projection). Close dots are recipes built alike. The lettered rings mark the middle of each group.

AB
Across →
More starter, fat and sweetener to the right; 34% of the variation.
Up ↑
More salt, water and starter upward; 27% of the variation.

The two groups

AClose to the overall median

131 recipes · 86% of all 152 · median oven 450°F (230°C), 30 min

Where it differs from all recipes

  • Fatmedian 0% vs 0% for all

    average rank: 44th percentile of all recipes · none in 96% (all recipes 85%)

  • Sweetenermedian 0% vs 0% for all

    average rank: 45th percentile of all recipes · none in 91% (all recipes 82%)

Its median recipe, at 500 g flour

Median recipe of group A in grams, against the median of all recipes
IngredientGroup AAll
Starter125 g125 g
Water345 g340 g
Salt10 g10 g
Fatnonenone
Sweetenernonenone

Each line is the group's median for that ingredient, scaled to 500 g of flour.

Closest to the middle of the group

BMore fat and sweetener

21 recipes · 14% of all 152 · median oven 440°F (225°C), 33 min

Where it differs from all recipes

  • Fatmedian 5% vs 0% for all

    average rank: 84th percentile of all recipes · none in 19% (all recipes 85%)

  • Sweetenermedian 3.5% vs 0% for all

    average rank: 79th percentile of all recipes · none in 28% (all recipes 82%)

  • Watermedian 60% vs 68% for all

    average rank: 31st percentile of all recipes

Its median recipe, at 500 g flour

Median recipe of group B in grams, against the median of all recipes
IngredientGroup BAll
Starter150 g125 g
Water300 g340 g
Salt11 g10 g
Fat25 gnone
Sweetener18 gnone

Each line is the group's median for that ingredient, scaled to 500 g of flour.

Closest to the middle of the group

How the groups are found

Each ratio is converted to a z-score (how many standard deviations a recipe sits from the mean), capped at 3 so one extreme recipe cannot claim a group, and k-means sorts the recipes into k groups, trying k from 2 to 4. Each k runs from 16 fixed starting points and keeps the tightest result, so the page is the same on every build. No group may hold fewer than 16 recipes.

The number of groups is the one with the best silhouette, which compares how close each recipe is to its own group with how close it is to the next one. By number of groups: 2 groups 0.42 · 3 groups 0.24 · 4 groups 0.23. At 0.25 or more the page calls the groups separate; from 0.18 to 0.25, overlapping; under 0.18, no clear styles.

A group's name lists the one to three ingredients where its recipes rank furthest from the middle of all 152, on average. “More” and “less” are relative to the whole dataset, and the names say nothing about texture or taste, which the ratios alone do not show. The median recipe of a group is, like the typical recipe on the overview, the middle of each ingredient separately, not one real recipe. The recipes listed under each group are the ones nearest its center, at most two from any one site.