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Tannic Acid Storage — Polyphenolic Gallotannin Tank Selection

Storing Tannic Acid? Start Here

Tannic acid is a versatile chemical used in leather tanning, water treatment, and more. It's a plant-derived polyphenol, appearing as a light-tan to brown powder with a mild astringent taste. When dissolved in water, it forms a mildly acidic solution, often used in concentrations from 1% to 10%. If you're considering storing tannic acid, it's crucial to choose the right tank material to avoid any unwanted reactions, especially with metals.

Can you store it in a poly tank?

Yes, you can store tannic acid in a polyethylene (poly) tank. High-density polyethylene (HDPE) and cross-linked polyethylene (XLPE) are both suitable for storing tannic acid solutions at all concentrations. These materials resist the mild acidity of tannic acid and are standard for such applications.

Watch out for iron staining

One key issue with tannic acid is its tendency to form dark iron-tannate complexes when it contacts iron or steel. This can lead to staining and potential contamination of your product. Always avoid using carbon steel or galvanized steel in any part of your storage system to prevent this reaction.

The safety that actually matters

  • Always use acid-resistant materials to avoid corrosion.
  • Prevent contact with iron to avoid staining and contamination.
  • Ensure proper ventilation to handle any fumes safely.

Common questions

What type of gaskets should I use?
EPDM gaskets are standard for tannic acid solutions. For beverage applications, consider Viton (FKM) seals.
Can I use stainless steel tanks?
Yes, 316L stainless steel is suitable for beverage and pharmaceutical applications. Avoid 304 stainless for concentrated solutions due to pitting risks.
Is tannic acid safe for water treatment?
Yes, tannic acid is used as a natural coagulant in water treatment, offering a low-impact alternative to chemical coagulants.

Tannic Acid storage tanks from OneSource

For tannic acid storage, specify HDLPE_OR_XLPE rated to specific gravity 1.9. Verified, compatibility-matched options:

Confirm chemical compatibility and a ZIP freight quote with our team at 866-418-1777.

Storing a corrosive acid? Material of construction is everything.

Acids attack the wrong metals fast. These vendor-neutral guides help you match resin, liner, and containment to your acid and concentration.

Explore: FRP & Fiberglass Tanks  ·  Double Wall Tanks  ·  Chemical Compatibility

Sources & References

All compatibility ratings, hazard classifications, and chemical identifiers on this page are sourced from authoritative third-party publications. Verify against the original references before final specification.

  1. PubChem Compound Database — entry for Tannic Acid (CID 16129778, CAS 5424-20-4). pubchem.ncbi.nlm.nih.gov. National Library of Medicine / NCBI. Canonical chemical-identity reference.
  2. Snyder Industries Chemical Resistance Recommendations — system-of-construction guidance for polyethylene chemical-storage tanks at industrial ASTM 1.9 SG design rating. SNY-3041 Chemical Resistance Chart. Snyder Industries, current edition. Resin + fitting + gasket + bolt MOC matrix.
  3. Equistar Technical Tip — Chemical Resistance of Polyethylene — LDPE / MDPE / HDPE rating chart by concentration and temperature, distributed by Enduraplas. enduraplas.com (PDF). Equistar polyethylene resin chemical-resistance data, distributed via Enduraplas.
  4. NFPA 704: Standard System for the Identification of the Hazards of Materials for Emergency Response. nfpa.org. NFPA 704 'fire diamond' health/flammability/instability/special-hazard rating system (0–4 scale).
  5. UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS), current revision. unece.org/transport/ghs. GHS pictograms, signal words, and H-statement codes referenced in this guide.
  6. ASTM D1998 — Standard Specification for Polyethylene Upright Storage Tanks, current edition. astm.org. Cited as the design-specific-gravity standard (typically 1.9 SG) for industrial chemical-service polyethylene tanks.
  7. NIOSH Pocket Guide to Chemical Hazards — occupational exposure limits, PPE, and IDLH data for Tannic Acid. cdc.gov/niosh/npg. CDC / NIOSH chemical-specific occupational-safety reference.

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