Agar

Few ingredients survive a century and a half of attempts at replacement. Agar entered the microbiology laboratory in 1882 and never left, because nothing else on the market combines its three unpurchasable qualities: it survives autoclaving, holds a firm gel at incubation temperatures, and offers most organisms nothing to eat. Bakeries, tissue-culture rooms and dental laboratories arrived at the same conclusion by different routes. When a formulation needs a gel that behaves the same way on the thousandth batch as it did on the first, agar is still the default answer.

Not all agar, however, comes from the same weed, and the differences are not cosmetic. Gelidium yields a naturally strong, low-sulfate agar that microbiologists prize; Gracilaria needs an alkaline pre-treatment to convert its sulfate groups into the anhydrogalactose units that give a gel its backbone — skip that step and the gel barely sets. We source across both genera plus Gelidiella and Pterocladia, match each grade to the job it will do, and put the measured gel strength, gelling and melting temperatures, ash and micro counts on the certificate rather than in the brochure.

Where the Strength Comes From

From Shore to Powder: The Route Every Lot Takes

1. Washing and sorting — sand, shells and epiphytes removed before anything is heated.
2. Alkali pre-treatment for Gracilaria (skipped for Gelidium), followed by neutralising washes.
3. Hot-water extraction — 105–110 °C under pressure for Gelidium; 95–100 °C atmospheric for Gracilaria.
4. Press and fine filtration of the hot extract, kept above gelling temperature throughout.
5. Gelation on cooling belts, then water removal by freeze–thaw cycles or mechanical syneresis — the purification happens here, as salts and soluble impurities leave with the water.
6. Drying and milling to an 80–100 mesh free-flowing powder, or cutting into strips for the traditional form.

Grades We Supply

Powder, Strips or Custom Mesh

• Powder — milled to 80–100 mesh as standard; finer or coarser cuts on request for dissolution speed versus dust control.
• Strip / bar agar — the traditional translucent form, still specified by some bakeries and craft industries.
• Instant agar — pre-hydrated grade that disperses in cold systems where a hot add is impractical.
• Blends — agar–locust bean and agar–gelatin systems tuned to a target texture.

The Numbers That Decide a Batch

• Gel strength by standard Nikan–Sui method at 1.5% concentration.
• Gelling temperature 34–50 °C and melting temperature 85–100 °C, quoted per genus.
• Moisture <15%, ash <3% (grade dependent), pH 6.0–7.5 in solution.
• Clarity and colour on a standard gel cast.
• Microbiological limits — total plate count, yeasts and moulds, Salmonella absent — on every lot destined for media use.
• Heavy metals by ICP-MS with harvest-region traceability.

Where Our Agar Ends Up

• Culture media — nutrient, blood and selective media bases, plus media-grade blends for diagnostic manufacturing.
• Plant tissue culture — firm, clear gels at 6–8 g/L that support orchids, ornamentals and vegetable explants through weeks of incubation.
• Food development — vegan gelatin replacement, heat-stable glazes and icings, suspension of fruit and inclusions, dairy and plant-based desserts.
• Pharmaceutical research — capsule and tablet disintegration work, emulsion stabilisation, hydrogel formulation studies.
• Industrial trades — dental impression compounds, textile sizing, paper coatings, adhesive formulations.

Tuned to Your Process

If the catalogue stops short of what your line needs, that is usually where the conversation gets interesting. Gel strength windows can be targeted rather than ranged — say, 1,050 ± 50 g/cm² — mesh cuts adjusted to your dissolution equipment, and blends formulated against a texture you supply as a reference. Strip-to-powder conversions, mixed-genus sourcing for cost or colour targets, and private-label packaging from 100 g bottles to 25 kg drums round out the options. Samples ship with the same certificates as production lots, so what you test is what you will receive.

Tell us the gel strength, form and volume your application calls for, and we will come back with the matching grade and its full lot data.

For Research or Industrial Raw Materials, Not For Personal Medical Use!