Glycerine is one of the safest chemicals a plant can handle: non-toxic, non-flammable at normal temperatures and gentle on skin. The problems it causes are physical. It is very thick, it pulls water out of the air, and it slows down even more when it gets cold. A few simple habits keep it in specification and stop it wasting time on the shop floor.
It is thick, and gets thicker
Pure glycerine is roughly 1,000 times more viscous than water at room temperature, and its viscosity rises steeply as temperature falls. A drum that pours slowly in a Chennai summer may barely move in an air-conditioned store or a North Indian winter. Very pure glycerine can even crystallise if kept cold for a long time, although it usually stays as a supercooled liquid.
Emptying drums and IBCs
- Keep stock in a warm part of the warehouse for a day before use.
- For faster flow, warm it gently to 35–45°C with a drum heater, warm-water jacket or hot room. Avoid direct flame and very hot surfaces, which can darken the colour.
- Tilt drums on a drum cradle and allow time to drain fully. Glycerine left in the corners of drums adds up to real money.
- Use wide-bore lines and positive-displacement pumps (gear, lobe or drum pumps rated for viscous liquids), not small centrifugal pumps.
Keep the water out
Glycerine is hygroscopic: it absorbs moisture from humid air. An open drum in Chennai's humidity slowly gains water and its assay falls. That matters if you are buying IP (99.5%) grade for medicines or cosmetics. Close drums straight after use, fit desiccant breathers to tanks and avoid long-term storage in part-empty containers. If assay matters to you, test before use and compare with the COA. See storing hygroscopic materials and moisture content explained.
Containers and materials
Stainless steel, aluminium, HDPE and lined steel are all suitable. Plain carbon steel can add iron to the glycerine over time and discolour it, which matters for pharma and cosmetic grades.
Grades and purity
- IP / USP glycerine (99.5%): for medicines, food, toothpaste and cosmetics. It must be tested for diethylene glycol and ethylene glycol and come with a batch COA.
- Industrial or technical glycerine: for alkyd resins, explosives, antifreeze, textiles and other non-ingestible uses.
Never move industrial glycerine into a pharma or food store. Our post on propylene glycol vs ethylene glycol explains why DEG/EG testing matters. We supply glycerine from Chennai stock.
Frequently asked questions
Why is glycerine so thick?
Glycerine molecules have three hydroxyl groups that bond strongly with each other, which makes the liquid very viscous: roughly a thousand times thicker than water at room temperature, and thicker still when cold.
Does glycerine absorb water from the air?
Yes. It is hygroscopic, so an open container gains moisture and its assay drops over time. Keep drums closed and tanks fitted with desiccant breathers.
How can I make glycerine flow faster from a drum?
Warm it gently to about 35–45°C in a hot room or with a drum heater, use a drum cradle to tilt it, and pump with a positive-displacement pump suited to viscous liquids.
This article is general guidance. Always follow the Safety Data Sheet and your own site procedures for the specific product and grade you use.