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Additives & Chemicals
Sodium Hydroxide Pellets (1000g)
Caustic soda pellets for degreasing glassware and gear and for nudging the pH of substrate water upward. A strong base that needs care, not a pasteurising shortcut.
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Supplied in a sealed HDPE screw-top container. Read the safety section before you open it.
Sodium hydroxide (caustic soda), CAS 1310-73-2, 99 percent pearls.
Degreasing glassware, jars and tubs, and raising water pH.
Corrosive to skin and eyes. Gloves and eye protection every time.
The short version
Sodium hydroxide, also called caustic soda or lye, is a strong alkali. These are white pellets (pearls) that dissolve in water and push the pH right up. Around the lab and grow room it is most useful for cutting through grease and protein residue on glassware, jars and tubs, and for nudging the pH of substrate water.
It is corrosive. It burns skin and eyes, gives off heat as it dissolves, and reacts with aluminium, zinc, tin and brass to release hydrogen. Treat it with respect and it is a cheap, simple tool. It is not a pasteurising agent for straw, and it does not replace a pressure cooker.
What it is
What you are buying
Sodium hydroxide pellets, sold as caustic soda or lye. The pearls are white and hard. They pull moisture and carbon dioxide straight out of the air, so the container stays sealed until you use it. Left open they soften, clump and slowly turn to sodium carbonate, which is a weaker base, so a tired open pack does less than a fresh one.
This is a chemical, not a living product. There is no origin story here. It does one thing well, which is make water strongly alkaline, and the uses below all follow from that.
| Chemical | Sodium hydroxide (caustic soda, lye) |
|---|---|
| CAS number | 1310-73-2 |
| EC number | 215-185-5 |
| Formula | NaOH, molar mass 40.0 g/mol |
| Form | White pellets / pearls |
| Purity | 99 percent |
| Pack | 1000 g in a sealed HDPE screw-top container |
How to use it
Cleaning and pH around the grow room
The well-supported uses are cleaning and pH adjustment. Always add the pellets to cool water, a little at a time, and stir. Never pour water onto the pellets, as that can boil and spit. The water heats up on its own as the pellets dissolve, so add slowly and let it settle.
Degreasing glassware, jars and tubs
A solution of roughly 10 to 20 g per litre (a 1 to 2 percent solution) strips grease, oil and protein residue off glass and lab gear. Make it up in a heat-safe container, soak the items, then rinse very well with clean water until the rinse runs clear. Caustic etches glass over time, so soak for the shortest time that works and do not leave glass in it overnight. Lab base bath procedures say not to let glassware soak for more than one night for the same reason.
Raising water pH
Because it is such a strong base, a very small amount lifts pH a long way. Add tiny pinches to your water, stir, and check with a meter or paper between additions. Go slowly. It is easy to overshoot, and bringing a too-high pH back down is fiddly, so add less than you think you need.
Rinse, and let pH settle
If you have treated anything that mycelium will later touch, rinse hard and let the pH come back toward neutral before you use it. Sodium left behind is not good for fungi.
Add caustic to water, never water to caustic. Use a heat-safe HDPE or borosilicate container, not aluminium, zinc, tin or brass, which it attacks and which can release flammable hydrogen gas. Stainless steel is fine.
No overselling
What this is not for
Caustic soda is sometimes suggested for cold pasteurising straw or coco by raising the pH. We are not going to sell it to you on that basis. The standard agent for high-pH straw baths is hydrated lime (calcium hydroxide), used at about 2 g per litre with a 16 to 20 hour soak. Sodium ions are mildly toxic to fungus and lime also adds useful calcium, so caustic soda is a poor fit for that job. If high-pH pasteurisation is what you want, choose lime, not this.
It is also not a substitute for proper sterilisation of grain or bulk substrate. High pH knocks back some bacteria and moulds, but it does not replace a pressure cooker or autoclave for a true sterile process.
Safety and storage
Handling, storage and first aid
This is a corrosive product. The signal word is Danger. It is corrosive to metals (H290) and causes severe skin burns and serious eye damage (H314). Wear chemical-resistant gloves and eye protection every time, do not breathe the dust, and work somewhere with good air flow.
If it gets on skin, wash at once with plenty of water and seek medical advice. If it gets in eyes, rinse cautiously with water for several minutes, remove contact lenses if you can, keep rinsing, and get medical help straight away.
Store the container tightly closed in a cool, dry place. The pellets are hygroscopic, so an open or loose container draws in moisture and carbon dioxide and clumps. Keep it away from acids and from aluminium, zinc, tin and brass.
Common questions
Frequently asked
You can raise pH with it, but we do not recommend it. Hydrated lime is the standard for high-pH straw baths, and the sodium in caustic soda is mildly bad for fungi while lime adds useful calcium. Use lime for that job.
This is 99 percent caustic soda sold for cleaning and pH use. A separate FCC food grade (E524) exists for food processing, but treat this stock as a cleaning and lab chemical and rinse anything it touches.
Always pellets into cool water, a little at a time, while stirring. Water onto solid caustic can boil and spit. The mix heats up on its own, so add slowly and let it settle.
A heat-safe HDPE or borosilicate glass container. Stainless steel is fine. Never aluminium, zinc, tin or brass, which it attacks and which can give off flammable hydrogen gas.
A short soak and a thorough rinse is fine. Caustic slowly etches glass, so do not leave glass soaking overnight. Lab base bath procedures say not to let glassware soak for more than one night for this reason.
Tightly closed in a cool, dry place. The pellets pull moisture and carbon dioxide from the air, clump, and slowly turn to weaker sodium carbonate if left open.
A 1 to 2 percent solution, about 10 to 20 g per litre, for grease and protein residue. Soak briefly, then rinse very thoroughly.
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Questions and answers
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Corrosive. Causes severe skin burns and serious eye damage. Keep out of reach of children. Sold for cleaning, laboratory and pH-adjustment use; not for consumption. Follow the supplier safety data sheet.
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