MSG is not L-glutamic acid
Worth settling first. L-glutamic acid is the free amino acid: poorly soluble and acidic. Monosodium L-glutamate is its sodium salt: highly soluble, near neutral, and strongly umami.
Choose MSG for seasoning; choose the free acid for amino acid nutrition or where you cannot move pH. A request for “glutamate” can mean either in practice. One line about the application at enquiry stage prevents the wrong sample arriving.
Production — fermentation
MSG is produced by microbial fermentation of molasses or starch sugar. Historic routes such as wheat protein hydrolysis and chemical synthesis are no longer the commercial norm; current material is essentially all fermentation-derived.
That route matters for allergen documentation, and whether the feedstock is cane molasses or corn bears on non-GMO handling. When qualifying a second source, compare feedstock as well as price. FONTIA’s monosodium L-glutamate is fermentation-derived.
Crystal size — where the decision actually sits
Assay specifications (99% min) are near-identical across suppliers, so comparing specification sheets tells you little. Crystal size is what differentiates in use.
- Fine / small crystal — suits powder seasoning blends. Mixes uniformly and resists separation from other powders
- Medium / large crystal — for systems that dissolve anyway. Slower to dissolve, but less dusting and easier to weigh
Using large crystal in a dry blend invites segregation by density and particle size during transport and storage. When the top and bottom of a sack taste different, this is usually why. It does not appear at bench scale — it appears in production and distribution.
What to check on the specification
- Assay — compendial, and whether on dried basis or as-is
- Particle size distribution — the main axis; specify by mesh
- pH — of aqueous solution; feeds into your formulation pH design
- Specific rotation — confirms the L-form; defined in the compendium
- Heavy metals and arsenic — compendial or in-house
- Feedstock — for allergen and non-GMO documentation
Food grade and feed grade
MSG sits under both food additives and feed additives. Food sanitation law and the Feed Safety Act impose different specification items and documentation, so state the intended application when requesting a quotation.
FONTIA supplies from prototype-scale lots upward. For specifications, samples or a quotation see the product page or use the contact form. Related: seasoning and umami ingredients / amino acid ingredients.