Why Has My DMSO Crystallised? DMSO Storage, Purity and; Handling Questions Answered

If you’ve opened your DMSO and discovered crystals, cloudy-looking solids or even a bottle that seems completely frozen, you might understandably wonder whether something has gone wrong.

The good news is that crystallisation is a completely normal characteristic of DMSO.

Unlike water, Dimethyl Sulfoxide has a relatively high melting point of around 18°C. That means pure DMSO can start turning from a liquid into crystals simply because the temperature in your cupboard, shed, warehouse or delivery vehicle has dropped.

So, why does DMSO crystallise, how should you store it, and what should you do when it turns solid?

Here are some of the most common questions about DMSO storage, purity and handling.

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Why does DMSO crystallise?

Pure DMSO has a melting point of approximately 18.5°C.

That is unusually high for a liquid solvent and means DMSO can begin crystallising at temperatures that don't feel particularly cold to us.

During winter, air-conditioned storage, transport or simply a cool night, you may notice:

• Small clear or white crystals forming inside the bottle
• A slushy or partially solid appearance
• Large crystals throughout the liquid
• The entire contents becoming solid

This is a physical change caused by temperature, rather than an automatic indication that there is something wrong with the DMSO.

Does crystallised DMSO mean it has gone bad?

No. Temperature-related crystallisation alone does not mean your DMSO has spoiled or lost its quality.

Once gently warmed above its melting point, the crystals should return to a clear liquid.

In fact, crystallisation is one of the more unusual but completely normal characteristics of high-purity DMSO.

However, DMSO should still be stored correctly to minimise exposure to moisture, contaminants and incompatible materials.

How do I turn crystallised DMSO back into liquid?

If your DMSO has crystallised, gently warming the sealed bottle will return it to its liquid state.

For smaller bottles, you can:

1. Make sure the bottle is tightly sealed.
2. Allow it to warm naturally in a room above its crystallisation temperature.
3. Alternatively, place the sealed bottle inside a sealed bag and sit it in warm water.
4. Allow the crystals to gradually melt before use.

Avoid excessive heat and do not microwave DMSO.

Keeping the bottle tightly sealed while warming is particularly important because DMSO readily attracts moisture from the surrounding air.

Why is keeping DMSO tightly sealed so important?

DMSO is hygroscopic, which means it readily absorbs moisture.

Leaving the bottle open unnecessarily can allow moisture from the surrounding atmosphere to enter the product. For a high-purity chemical product, limiting exposure to moisture and other contaminants helps maintain its intended specifications.

Always replace the cap promptly after use and store the bottle tightly sealed.

This is also one reason we recommend leaving DMSO in its original packaging rather than transferring it into an unverified container.

How should DMSO be stored?

For everyday storage, keep DMSO:

• Tightly sealed
• In a cool, dry location
• Away from direct sunlight
• Away from incompatible chemicals and materials
• In its original or another verified DMSO-compatible container
• Out of reach of children

If the storage area drops below approximately 18°C, crystallisation may occur. Again, this is normal and the DMSO can be gently returned to liquid form before use.

There is generally no reason to deliberately refrigerate DMSO. In fact, doing so will almost certainly cause it to crystallise.

Should DMSO be stored in glass?

Glass is a commonly used material for DMSO because of its chemical compatibility.

DMSO is a powerful solvent, so not every plastic, rubber or container material is suitable for prolonged contact with it.

Some chemical-grade materials, including certain polyethylene, polypropylene and PTFE products, can be compatible with DMSO. However, this doesn't mean any household plastic bottle or container is suitable.

If you're unsure, keeping the product in the packaging it was supplied in is the simplest option.

Kemmie's new 100ml DMSO is supplied in an amber glass bottle with a glass dropper, providing a convenient smaller-volume format while keeping the product contained in glass.

Why can DMSO sometimes develop an odour?

High-purity DMSO is normally colourless, transparent and essentially odourless.

However, DMSO can develop a noticeable odour following exposure to air, moisture or other impurities.

For this reason, a tightly sealed container and clean handling practices are important.

If your DMSO develops an unexpected change in appearance or a significant odour, check that the product has been stored correctly and refer to its product specifications or safety documentation before use.

What does 99.9% pure DMSO mean?

Kemmie DMSO has a minimum assay of 99.9% purity by gas chromatography (GC).

Gas chromatography is an analytical testing method used to separate and measure chemical components within a sample.

Purity is particularly important for a chemical solvent because water, residues and other impurities can affect how the material behaves in different applications.

Kemmie DMSO is tested to USP38 specifications, with requirements covering factors including:

• Assay
• Moisture
• Acidity
• Optical clarity

Our DMSO is also identified by CAS 67-68-5, the internationally recognised Chemical Abstracts Service number for Dimethyl Sulfoxide.

Does USP Grade mean DMSO is approved for medical use?

No.

This distinction is important.

A USP specification relates to the quality and testing standards a material meets. It does not automatically determine how a particular product is approved, registered or intended to be used.

Kemmie DMSO is supplied as a general-purpose solvent and chemical ingredient only.

It is not supplied or marketed for therapeutic, medical, cosmetic or ingestible use, and no therapeutic claims are made.

Always determine whether a chemical is suitable for your particular application and follow the appropriate safety, handling and regulatory requirements.

What is DMSO used for?

DMSO is a highly versatile solvent used across laboratory, industrial, commercial and manufacturing environments.

Its applications can include use as a solvent or chemical intermediate in:

• Coatings and paints
• Lacquers and varnish removers
• Cleaning products
• Inks
• Fillers and modelling clays
• Polishes and wax blends
• Adhesives and sealants
• De-icing and anti-freeze formulations
• Hydraulic fluids
• Construction materials

Its strong solvent properties are also why appropriate handling and container compatibility are important.

Is DMSO safe to handle with bare hands?

Avoid direct skin contact with DMSO and use appropriate chemical-handling practices.

DMSO is an effective solvent and can penetrate the skin, so care should be taken when working with it, particularly where other chemicals or contaminants may also be present.

Always refer to the product label and Safety Data Sheet for appropriate handling, storage and personal protective equipment.

Now available in a 100ml glass dropper bottle

For applications that only require a smaller quantity, Kemmie DMSO USP Grade 99.9% Min is now available in a convenient 100ml amber glass bottle with glass dropper.

The smaller format makes it easier to dispense controlled amounts without purchasing a larger container, while the glass packaging provides a suitable container for DMSO storage.

Kemmie DMSO is a colourless, transparent, high-purity solvent tested to USP38 specifications and supplied for general-purpose chemical and solvent applications.

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Quick DMSO storage checklist

Keep your DMSO:

• Tightly sealed
• Cool and dry
• Away from direct sunlight
• In its original or verified compatible container
• Protected from unnecessary moisture exposure

And if you open the cupboard one day to find a bottle full of crystals, don't panic. At around 18°C, DMSO is simply doing what DMSO does.

Gently warm the sealed bottle and it should return to its clear liquid state.

Shop Kemmie DMSO

Available in our new 100ml amber glass dropper bottle and larger sizes for applications requiring greater volumes.

Disclaimer: Kemmie DMSO is supplied as a general-purpose solvent and chemical ingredient only. It is not intended for therapeutic, medical, cosmetic or ingestible use. No therapeutic claims are made. Users are responsible for determining suitability for their intended application and following appropriate safety and handling practices.