Cheese crystals are whitish, semi-solid to solid, slightly crunchy to gritty crystalline spots, granules, and aggregates that can form on the surface and inside of cheese. Cheese crystals are characteristic of many long-aged hard cheeses.
Hard cheeses where cheese crystals are common and valued include comté, aged cheddar, grana cheeses like parmesan, grana padano, and Pecorino Romano, as well as old gouda. However, in some cheeses, like industrial cheddar, they are considered a production defect.
Cheese crystals can consist of different substances. Most commonly found are calcium lactate crystals, especially on younger cheese, on the surface, and on cheddar. Depending on the cheese and its age, these crystals can consist of either or both enantiomers. For grana padano, grainy amino acid crystals inside the cheese consisting mainly of tyrosine and of leucine and isoleucine have been reported. In general, any substance that has a low solubility in water and a tendency to crystallize could form crystals as the cheese dries out during aging.
- Phadungath, Chanokphat (2011). The Efficacy of Sodium Gluconate as a Calcium Lactate Crystal Inhibitor in Cheddar Cheese (Thesis). University of Minnesota. Retrieved October 12, 2013.
- Stephie Clark & Shantanu Agarwal (April 27, 2007). "Chapter 24: Cheddar and Related Hard Cheeses. 24.6: Crystal Formation". In Y. H. Hui (ed.). Handbook of Food Products Manufacturing (1st ed.). Wiley-Interscience. p. 589. ISBN 978-0470049648.
- A. Bianchi; G. Beretta; G. Caserio; G. Giolitti (1974). "Amino Acid Composition of Granules and Spots in Grana Padano Cheeses". J. Dairy Sci. 57: 1504–1508. doi:10.3168/jds.s0022-0302(74)85096-4.