Enriched sandwich breads often cool with a gelatinous or gummy center because their ingredients and baking conditions prevent the crumb from fully setting during the bake. This outcome is primarily a structural issue: the starches and proteins that must coagulate and gelatinize to form a stable crumb never reach the state needed in the loaf's core.
Why it happens
Baking science identifies starch gelatinization
Ingredient and process roles
Enriched doughs contain elements that retain moisture and interfere with structure. Fats and oils coat starch and protein, impeding water uptake and slowing gelatinization. Sugars compete for water and raise the dough’s thermal buffering, so more oven time or higher internal temperatures are needed. High hydration formulations and the use of diastatic malt or active enzymes can leave more soluble starch and dextrins that feel sticky after cooling. Jeffrey Hamelman at King Arthur Flour highlights that enriched breads typically require a lower finished internal temperature than lean crusty breads, but they still must reach a sufficient core temperature—commonly targeted around 88–93°C—to avoid a doughy center.
Cultural and practical nuances matter: home ovens, ambient humidity, and pan size influence how heat penetrates a loaf. Commercial bakeries use larger pans and higher-throughput ovens that alter heat flow compared with a domestic oven, so a recipe that bakes well commercially can finish gummy at home if not adjusted.
When the center is undercooked, the consequence is both sensory and economic: a loaf that slices poorly, wastes ingredients, and frustrates bakers. Addressing the problem requires understanding the interplay of ingredients, proper internal temperature, and oven behaviour so that the crumb can complete the physical transformations that produce a stable, non-gummy sandwich bread.