Disodium Hydrogen Phosphate (DSP) — Frequently Asked Questions

They are the same salt with different amounts of water of crystallisation. Anhydrous DSP contains almost none, the dihydrate about 20 % water and the dodecahydrate about 60 %. Performance per unit of phosphate is identical, but the dose changes: 1 kg of anhydrous equals about 1.25 kg of dihydrate or 2.52 kg of dodecahydrate. Always check which form a recipe or specification refers to.

Heat treatment and concentration upset the balance between calcium, phosphate and casein, which can make milk thicken, gel or coagulate during sterilisation and storage. DSP buffers the pH and binds part of the calcium, keeping the proteins stable. In coffee creamers it also helps prevent feathering when the creamer meets hot, acidic coffee. The right level depends on the seasonal composition of the milk and is set by trial.

Both are effective buffers and protein stabilisers. DSP is the traditional, economical choice in dairy and processed cheese. Dipotassium phosphate adds no sodium and is more soluble, which suits reduced-sodium products, creamers and ready-to-drink protein beverages. The two are sometimes combined. Sensory differences are small at normal levels, so the choice usually comes down to sodium targets, solubility and cost.

It exchanges sodium for calcium in the cheese protein network. This makes the casein more soluble so it can hydrate, swell and coat the fat droplets, producing a smooth, homogeneous melt. DSP also buffers the pH, which affects texture and meltability. It is normally used in blends with polyphosphates or citrates, chosen according to whether a sliceable block, spread or sauce is required.

Yes. In most categories the EU and UK set a single maximum for phosphates E338 to E452 combined, expressed as P2O5, and DSP counts towards it together with any other added phosphates. Anhydrous DSP contains about 50 % P2O5, so convert your addition rate on that basis and check the limit for your category in the current Annex II of Regulation (EC) No 1333/2008 or the UK retained equivalent.

Specify the form (anhydrous, dihydrate or dodecahydrate), particle size, the application and the purity standard (E339(ii), FCC or JECFA). Add the pack size, annual volume and destination, and list the documents your approval process requires, such as the specification, safety data sheet and a batch certificate of analysis.