Agar Bioplastic

What It Is

Agar agar is a polysaccharide extracted from the cell walls of red algae (Rhodophyta) — primarily Gelidium, Gracilaria, and Pterocladia species. When dissolved in hot water and allowed to cool, it forms a firm gel. Mixed with glycerin as a plasticizer and cast into thin layers, it dries into a flexible bioplastic film that sits somewhere between plastic, skin, and paper.

Bioplastics are materials made from biopolymers derived from natural biomass. They typically include a biopolymer, a plasticizer, and sometimes a colorant. Agar bioplastic is fully plant-based and fully compostable.

Why Artists Use It

Agar bioplastic appeals to artists working at the intersection of material research, ecological practice, and sensory experience. It is translucent — allowing embedded botanicals, photo prints, and pigments to show through. It responds to humidity, light, and temperature in ways that feel alive. And it degrades: making it a material with a timeline, not just a surface.

At Material Memory Studio, agar bioplastic is used primarily for botanical embedding — pressing flowers, plants, and photographic prints into cast sheets. The resulting objects hold memory in the most literal sense: a flower from a specific night, a specific garden, a specific season.

Agar also serves as a photographic substrate: a 2% agar solution can be poured onto glass plates for cyanotype printing, replacing gelatin which reacts poorly with the chemistry's humidity and acidity.

Historical Context

Agar was first isolated in Japan in the 17th century as a culinary gelling agent (kanten, 寒天). It entered scientific use in the 19th century when Angelina Fanny Hesse proposed it as a microbiology culture medium. Its application in art and design biomaterial practice emerged primarily in the 2010s through programs like Fabricademy and open-source repositories including Materiom and Margaret Dunne's Bioplastic Cook Book.

Basic Recipe

The following ratios are from Jay Lee's bioplastic workshop, adapted from Margaret Dunne's open-source recipe book:

	Brittle			Flexible
Glycerin (g)	0.0	1.4	2.7	5.4
Water (ml)	40	40	40	40
Agar (g)	1.6	1.6	1.6	1.6

1. Add agar, water, and glycerin into a pot.
2. Cook over medium heat, stirring continuously, until the solution boils and becomes sticky (20–30 min).
3. Remove any froth with a spoon — this ensures a glossy, smooth surface.
4. Tape a wooden frame onto a non-stick surface (glass, laminate, Mylar, or PVC) and pour in.
5. Partially cool before embedding botanicals or objects.
6. After 24 hours, remove the frame and hang-dry for 1–7 days depending on thickness and humidity.

For cyanotype glass plates: 7.5g agar / 375ml water (2% solution). Warm the glass with a hairdryer first to prevent thermal shock, then pour the warm agar directly onto the plate.

Tools & Safety

• Kitchen scale, small saucepan, silicone spatula, wooden frame or mould
• Non-stick surface: silicone mat, laminate, linoleum, Mylar film, PVC roll, or lightly oiled glass
• Antibacterial spray to sterilize workspace and tools

Agar agar and glycerin are both food-safe and non-toxic. Work carefully with hot liquid.

Common Failures

• Shrinking (up to 20%): Agar bioplastic shrinks significantly as it dries. Cut free from frame edges after 24h to allow controlled movement. Do not force-dry.
• Cracking: Too-fast drying or insufficient glycerin. Increase glycerin and dry slowly at room temperature, away from direct sun or heat.
• Mould: Agar is compostable — it decays in humid conditions. Sterilize all embedded organic materials (boil and dry fully before use). Isolate mouldy pieces immediately.
• Bubbles / foam: Heated too quickly or stirred too vigorously. Heat slowly and gently. Remove froth before pouring.
• Sticking to the surface: Use proper non-stick surface. Lightly oil glass if needed.
• Uneven thickness: Work on a level surface. Act quickly — agar begins to set below 40°C.

Archival Notes

Agar bioplastic will biodegrade over months to years depending on humidity and temperature. Store flat between acid-free tissue in a cool, dry environment (below 50% relative humidity). Avoid prolonged moisture contact. A thin coat of natural beeswax can slow degradation and add sheen, though this partially compromises compostability.

Jay's Studio Note

At Material Memory Studio in Seoul, agar bioplastic became the core material of the Botanicals workshop — using flowers from the studio's opening night (April 2026) as embedded inclusions. The flowers were pressed and dried first, then cast into agar sheets. The result holds the specific fragrance and shape of that April evening — not as decoration, but as material evidence. In an earlier CDMX studio practice, food scraps — egg shells, garlic peels, mandarin peels — were embedded alongside found street materials. The bioplastic became a way of collecting place.

Related Materials

Gelatin Bioplastic — animal-based alternative, stronger, no boiling · Botanical Embedding — technique for embedding plants and photos · Cyanotype on Glass — agar as photographic coating (2%) · Alginate — different gel mechanism, calcium-based setting

References

• Margaret Dunne, Bioplastic Cook Book (open source) — issuu.com/nat_arc/docs/bioplastic_cook_book_3
• Materiom.org — open-source biomaterial recipe database
• The Material Way (thematerialway.com) — natural material courses