Grade · LA
Low acyl gellan gum — firm, brittle, heat-stable gels
Low acyl is the deacylated grade. It sets into a firm, brittle network that breaks with a clean snap, and once that network has formed it does not melt again in a normal process. That is why it carries every application where the gel has to survive heat.
Key figures
- Low acyl gellan gum sets at approximately 30–50 °C on cooling, rising with calcium concentration, and melts at 85–105 °C.
- Low acyl gellan gels are thermo-irreversible in the presence of divalent cations, so the network survives a retort process.
- Low acyl gels are highly transparent, and the grade is highly sensitive to Ca²⁺ and Mg²⁺.
- Clear jelly and jelly cups use low acyl gellan gum at 0.1–0.3% with sodium citrate and a calcium source.
What to do
- Plan for a calcium source. Low acyl will not set without a free divalent cation — 0.02–0.05% calcium chloride is the usual starting point, or 0.05–0.10% calcium lactate if the chloride taste is a problem.
- Hydrate fully at 80–90 °C, with 75 °C sufficient in soft water and more needed in hard water, under shear. Partial hydration costs you both clarity and strength.
- If the formula is already rich in calcium, add a sequestrant so the gel does not form in the tank before filling.
Where this grade is the usual answer
- Clear jellies, jelly cups and gelled desserts
- Gelled drinks and popping boba, formed in a calcium bath
- Products that go through UHT, retort or baking
- Plant tissue culture media and microbiological media
- Any product where the gel must survive above 100 °C
Low acyl is the grade that fails when the water is wrong. The same dose can set in one plant and stay fluid in another, because the difference is the free calcium, not the powder.
The other two outcomes
A different answer, if your constraints differ
Other tools
Keep going
Three more decision aids for the same problem set.