How to Store Pottery Clay in Winter and Cold Weather
When the temperature drops, looking after your pottery clay becomes especially important. Cold garages, sheds and unheated studios can create problems for moist clay, particularly if the temperature falls below freezing overnight. Fortunately, a few simple storage habits can help keep your clay in good condition and ready for your next pottery project.
Whether you're a hobby potter working from home, a pottery teacher or running a busy ceramics studio, here's how to protect your bagged ceramic clay through the colder months.
Winter clay storage: the essentials
- Keep moist pottery clay in a frost-free location with a reasonably stable temperature.
- Leave clay in a securely sealed bag to help prevent moisture loss.
- Store bags away from cold floors, draughty doors and direct heat.
- Move winter deliveries into suitable storage promptly and check your stock regularly.
Why can freezing temperatures affect pottery clay?
Ready-to-use pottery clay contains moisture that helps make it workable for throwing, hand-building and sculpting. If that water freezes, the clay may feel uneven, crumbly or unusually firm after it thaws. It doesn't necessarily mean the clay is unusable, but it may need extra preparation before you can work with it comfortably again.
Choose a frost-free place to store your clay
A storage room or studio that remains above freezing is preferable to a shed or garage that becomes icy overnight. If your pottery workspace isn't heated continuously, consider using a minimum-and-maximum thermometer to see how low the temperature falls when you're not there. Don't assume that a room which feels comfortable in the afternoon will stay frost-free overnight.
Keep your bags on suitable, sturdy shelving or pallets rather than directly on concrete floors. Position them away from exterior doors, draughts and particularly cold walls. Insulation may reduce rapid temperature changes, but it won't guarantee protection against frost during an extended cold spell.
Keep pottery clay sealed so it doesn't dry out
Freezing isn't the only winter storage issue. Heated rooms can dry out clay if its packaging is left open. Keep unopened clay in its original sealed bag and reseal any opened bags carefully after use. If a bag has split, put the clay into a fresh, secure plastic bag or a suitable airtight container. If you divide a larger bag into smaller portions, wrap each portion securely in plastic before placing it in a sealed bag or airtight container to help prevent it drying out.
Avoid placing clay next to radiators, portable heaters or in prolonged direct sunlight, as warmth can encourage moisture loss if the packaging is not properly sealed. A stable environment and well-sealed packaging are much better than alternating between very cold and very warm conditions.
What if your stored pottery clay starts to dry out?
If your clay feels firmer than usual, it may be possible to make it workable again by gradually reintroducing a little clean water. Reseal the clay in a suitable bag or airtight container and allow time for the moisture to distribute more evenly before checking its consistency. Avoid adding too much water at once, as this can make the clay overly soft or uneven. Clay that has dried out completely may need to be reclaimed — which means adding water and working the clay back into a usable condition. Always follow the clay manufacturer's guidance.
When handling dried clay or reclaiming scraps, avoid creating airborne dust. Use wet-cleaning methods rather than dry sweeping, as some ceramic clay dust can contain harmful respirable crystalline silica.
Look after clay deliveries during cold weather
If you're expecting a delivery of pottery clay in winter, arrange to bring it into suitable storage as soon as practical. Try not to leave bags outside, in an unheated vehicle or by an exposed doorway overnight. Where you're ordering clay for a school, club or studio, plan a storage space before the delivery arrives, especially for larger quantities.
What if your pottery clay has already frozen?
Don't throw it away straight away. Frozen pottery clay can often be made workable again, although the result will depend on its condition. Try these simple steps:
- Let it thaw slowly. Move the sealed clay to a frost-free room and allow it to thaw completely. This may take a few days. Avoid radiators, heaters and other direct heat, which can dry the outside unevenly.
- Check the texture. Once fully thawed, feel whether the clay is smooth and workable or has become grainy, crumbly or uneven.
- Work the clay if needed. Cut it into manageable pieces and knead or wedge it to help even out the moisture and consistency. If it feels too firm or dry, a little clean water can be added gradually while working it; avoid making it too wet.
- Consider further reworking. Clay that is still difficult to use may need to be soaked, mixed and then allowed to lose excess water until it reaches a workable consistency again. This is a form of clay reclaiming, and it may not be suitable or successful for every clay body.
If you're unsure, follow the clay manufacturer's guidance before using the affected clay. When reworking dry clay, take care not to create airborne dust.
Looking after unfinished pottery in cold weather
Damp, unfinished pottery needs care too. If you're working on a piece over several days, cover it loosely with suitable plastic sheeting between sessions to slow moisture loss and encourage more even drying. Keep damp work in a frost-free location, away from draughts and direct heat. Check pieces regularly, especially handles and other attachments, which can dry at a different rate from the main body. Once you're ready to dry a piece fully before firing, allow it to dry evenly rather than keeping it tightly covered indefinitely.
Storing clay for a pottery studio, school or workshop
If you keep several bags or different clay bodies in stock, label them with the clay type and the date they were opened or stored, and check your storage area during prolonged cold spells. Keep opened bags properly closed, and organise your stock so older bags are easy to find and use. A simple routine can help reduce unnecessary waste and keep pottery sessions running smoothly when the weather turns colder.
These tips are intended for moist, ready-to-use pottery clay. Dry clay powders, liquid casting slips and air-drying craft products may have different storage instructions, so always follow the guidance for the particular product you're using.
Buying pottery clay for your next project?
Browse Cromartie's selection of pottery and ceramic clays, including earthenware, stoneware, porcelain, terracotta, raku and specialist clay bodies for different ways of working. We also stock clay tools for preparing, shaping, cutting and finishing your work.
Ordering larger quantities? We can help with bulk clay pricing for bigger orders. Email karen@cromartie.co.uk to enquire about pricing for your studio, school or workshop.