Fruit yogurt · Stability

Fruit Yogurt Syneresis (Whey on Top): Causes and Fixes

Short answer

Syneresis is whey separating from the yogurt gel and collecting on top during storage. In fruit yogurt it usually comes from low milk solids or protein, too little heat treatment of the milk, rough handling after fermentation, or a fruit preparation whose Brix and pH do not match the white mass. Gas, domed lids and dull fruit point to yeast and mold. The fix is to balance solids, heat treatment and the fruit-prep spec together.

Updated: 2026-11-05

Target: smooth, glossy, evenly pink strawberry yogurt with fruit pieces suspended. — Plate C · Stirred strawberry yogurt, day 21 at 40 °F / 4 °CSyneresis vs. stable gel

Defect: whey separated on top of a grainy, curdled strawberry yogurt with dull fruit. — Plate C · Stirred strawberry yogurt, day 21 at 40 °F / 4 °CSyneresis vs. stable gel

Fruit yogurt · Stability

Fruit yogurt with whey on top and a grainy body

1A layer of whey on top by mid shelf life (syneresis)
2Grainy, curdled texture with gas pockets; domed lids, yeasty notes
3Fruit pieces that break down, leach color and turn dull

Usual causes: Low total solids or protein, weak milk heat treatment, post-acidification below pH 4.2, shear in pumps and fillers, Brix and pH mismatch with the fruit prep, yeast and mold in fruit or filler
What we review: Mix formulation, heat-treatment records, fermentation and cooling curves, fruit prep spec and CoA, yeast and mold counts (CFU/g), filler sanitation and ATP swabs, shelf-life pulls
Typical levers: Solids and protein standardization, heat-hold targets, break pH and cooling speed, gentler transfer, fruit prep re-spec with your supplier, filler hygiene zoning

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