Picking a clay shouldn't be stressful, but it's easy to get lost when you're looking at a long list of options: earthenware, stoneware, porcelain, grogged, smooth, cone 6, cone 10. Which one actually fits what you do? And what if you buy the wrong one and spend the next few weeks fighting it?
The honest answer is that there's no single "best" clay. There's the right clay for you, and that depends on your skill level, your kiln, what you're making and how you like clay to feel in your hands. This guide walks through those choices one at a time.
A bit about our clay first. Sheffield Pottery makes its own clay. Every clay body is formulated, blended and pugged in-house on de-airing pugmills, so it arrives smooth, soft and ready to use straight out of the box.
Each 50 lb box holds two 25 lb sleeves, twist-tied and sealed so the clay stays moist. We make clay bodies for classrooms, community studios, professional potters and production shops.
The main types of pottery clay
All pottery clay is some combination of natural clays and minerals. How those materials are blended decides how the clay handles in the studio and how it behaves in the kiln.
We make clay bodies in four main groups:
- Earthenware
- Stoneware
- Porcelain
- Specialty clays (raku, sculpture and architectural)
Here's what each one is good at, and when to pick it.
Earthenware: easy to work and forgiving
Firing range: Cone 06 to Cone 02 (1828 to 2016°F)
Earthenware is a low-fire clay. It's the traditional clay for terra cotta, redware and decorative ceramics. Schools, hobbyists and decorative potters like it because it's forgiving and it shows off bright glaze colors.
What earthenware does well
It's easy to work. Earthenware is plastic and responsive, which makes it a good clay for beginners. It puts up with mistakes better than higher-fire clays and doesn't dry out as fast while you're throwing or hand-building.
It fires lower. Firing to cone 06 (1828°F) takes less energy than stoneware or porcelain, so it costs less to fire and is easier on your kiln elements. If you're working with a classroom budget or a small home kiln, that adds up.
It takes bright glazes. Low-fire glazes come in a huge range of saturated colors, including turquoises, yellows, oranges and purples you can't get at high fire. Earthenware's porous surface takes these glazes well.
It has warm fired colors. Depending on the body, earthenware fires to a terra cotta red, a soft buff or a clean white. Those colors look good under clear glaze, or left bare with terra sigillata or burnishing.
Where earthenware falls short
It stays porous. Even fired to maturity, earthenware doesn't vitrify, so it won't hold water on its own. If you want to use it for functional ware, glaze it fully inside and out.
It chips more easily than stoneware or porcelain. That's fine for decorative work, planters and serving pieces, but everyday dishes hold up better in a stronger clay.
It isn't frost-proof. Water soaked into the clay can freeze and crack it, so don't leave unglazed earthenware outside in a cold climate.
When to choose earthenware
- You're teaching beginners. It's forgiving and cheaper to fire, which suits a classroom.
- You're making decorative work: sculpture, wall pieces, decorative vessels and art pottery where function isn't the main point.
- You want bright glaze colors. Those electric blues and oranges are low-fire colors.
- You want to keep firing costs down. Lower temperatures mean a smaller electric bill over time.
We make low-fire red and white earthenware clays that are smooth, easy to form and well suited to classroom or studio use.
Stoneware: the everyday workhorse
Firing range: Cone 5 to Cone 10 (2167 to 2345°F)
Stoneware is the most widely used pottery clay. Most potters making functional ware (mugs, bowls, plates, serving pieces) use it, because it vitrifies fully and comes out of the kiln strong and watertight.
Why most studios use stoneware
It vitrifies. Fired to maturity, stoneware holds water without a glaze, which is what you want for pots that hold liquid, go through the dishwasher and get used every day.
It's tough. Stoneware resists chipping better than earthenware and stands up to real kitchen use: stacking, constant washing and the occasional drop.
It's good to throw. Our stoneware bodies are made for both wheel throwing and hand-building. They center easily, pull up without a fight and hold their shape while you build.
It gives you firing options. Mid-fire stonewares (cone 5 to 6) work well in electric kilns and have a big choice of glazes. High-fire stonewares (cone 9 to 10) do best in gas, reduction or wood kilns and give you the classic stoneware look.
It comes in a range of colors, from dark brown to light tan to nearly white. Choose based on the look you want and whether you want the clay color to show through your glazes.
Mid-fire vs. high-fire stoneware
Mid-fire (cone 5 to 6):
- Made for electric kilns
- Cheaper to fire than cone 10
- Lots of glazes to choose from
- Fully functional and durable
- Slightly less vitrified than cone 10, but still waterproof
High-fire (cone 9 to 10):
- The traditional stoneware range
- Best for gas, reduction or wood firing
- Highest vitrification and strength
- Classic ash glaze effects
- Costs more to fire
Our mid-fire (cone 5 to 6) stoneware bodies are formulated for electric kilns. Our high-fire (cone 9 to 10) stonewares are meant for gas, reduction or wood kilns.
When to choose stoneware
- You're making functional pottery. If people will eat and drink from it, stoneware gives you the strength and safety you need.
- You want one clay that does a bit of everything. Stoneware works for throwing, hand-building and sculpture.
- You have an electric kiln. Mid-fire stoneware is made for electric firing.
- You like the classic look. Stoneware gives the warm, earthy tones most people picture when they think of handmade pottery.
White stoneware: a middle ground
If you love the clean white of porcelain but want something easier to handle, try a white stoneware. It gives you a porcelain-like look with the forgiving feel of stoneware.
- Its bright white fired color shows glaze colors accurately
- It's more plastic, and easier to throw, than porcelain
- It's less likely to warp than porcelain
- It's fully functional and durable
- It's much friendlier to beginners than true porcelain
A lot of potters who struggled with porcelain find that white stoneware gets them the look they want with far less frustration.
Porcelain: beautiful, but it takes patience
Firing range: Cone 6 and Cone 10 (2232 to 2345°F)
Porcelain is known for its whiteness, its translucency and its fine, smooth surface. It's traditionally fired to cone 10 and gives you the delicate look of fine china.
What makes porcelain special
It's white and can be translucent. Thrown thin and fired properly, porcelain lets light through. No other clay body glows quite like that.
It has a smooth, refined surface. Fired porcelain feels almost like glass. Even unglazed, it looks finished.
It shows true glaze color. A white body doesn't muddy your glazes, so what you see in the bucket is close to what you'll get on the pot.
It has a long tradition. For centuries porcelain has been tied to fine dining and luxury, and it still carries that reputation.
Why porcelain is harder
It's less plastic. Porcelain is "short," meaning it has less natural plasticity than stoneware, which makes it harder to throw, especially for beginners. It can't take as much water on the wheel and will collapse if you overwork it.
It warps more easily. With no grog or coarse material in it, porcelain can warp in drying or firing if the form isn't well designed or the drying isn't controlled.
It takes practice. Most potters struggle with porcelain at first. It asks for cleaner technique, drier throwing and more attention to form than stoneware does.
It doesn't forgive much. Mistakes stoneware would let slide show up in porcelain. Uneven walls warp, rough handling cracks it, and rushed drying leads to losses.
Cone 6 vs. cone 10 porcelain
Cone 10 porcelain (traditional):
- The most translucent
- The classic porcelain look
- Needs a gas kiln or a high-fire electric kiln
- Costs more to fire
Cone 6 porcelain (modern):
- Works well in electric kilns
- Nearly as white as cone 10
- A little less translucent, but still refined
- Cheaper to fire
- Easier to get consistent results
Our porcelain bodies are blended with kaolin and ball clays to balance workability, strength and looks. We make both cone 6 and cone 10 versions, so you can pick the one that fits your kiln.
When to choose porcelain
- You're an intermediate or advanced potter. If you're comfortable with stoneware and want a new challenge, porcelain will give you one.
- You want that particular look. Nothing else looks quite like porcelain. If that's what your work needs, it's worth the learning curve.
- You're willing to change how you work. Porcelain means throwing drier, handling more gently and controlling drying more carefully.
- You sell your work. Porcelain's reputation can raise the perceived value of gallery and retail pieces.
Specialty clays: when a standard body won't do
Some jobs need a clay made for a specific purpose. We make specialty bodies for these.
Raku clay
Raku clay is built to survive extreme thermal shock: pots pulled out of an 1800°F kiln and dropped into combustible material or water.
- High grog content for thermal shock resistance
- An open body that tolerates fast temperature changes
- Formulated specifically for raku firing
- Not a good choice for functional ware, since it stays somewhat porous
Use it for raku, obvara or any process with sudden temperature changes.
Sculpture clay
Sculpture clay is for large, heavy forms that have to hold up their own weight while you build them and while they fire.
- Very high grog content for strength
- Lower shrinkage, so large pieces crack less
- Stands up well during hand-building
- Not great for throwing (too much grog)
Use it for large sculpture, architectural pieces and heavy hand-built forms.
Architectural clay
Architectural clay is for tiles, murals and building elements that need to be strong, flat and dimensionally stable.
- Controlled shrinkage, so sizes are predictable
- Stays flat through drying and firing
- Durable enough for permanent installations
- May include colorants for architectural work
Use it for tile making, murals and outdoor installations.
What is grog, and do you need it?
Grog is ground-up pre-fired clay or sand that's added to a clay body to change its texture and how it performs. Knowing what it does makes it easier to pick the right version of a clay.
What grog does
It adds tooth. Grog gives clay a slightly rough, grippy feel, which helps when you're throwing bigger or thicker forms because the clay doesn't slip between your hands as easily.
It cuts shrinkage. All clay shrinks as it dries and fires, because water leaves and the particles pack closer. Grog has already been fired, so it doesn't shrink. Adding it lowers the overall shrinkage and helps prevent cracks.
It improves thermal shock resistance. Grog opens up the clay body so it can handle fast temperature changes without cracking. That's why it's so important for raku and pit firing.
It strengthens large forms. Grog works a bit like rebar in concrete, giving big pieces the internal structure to hold up their own weight.
The trade-off
Grog makes clay less smooth. For delicate throwing, fine surface detail or thin walls, that can be a problem. The texture can show through glazes, and it can be rough on your hands over a long throwing session.
How much grog to choose
We make many of our clay bodies both with and without grog, so you can pick the feel that suits how you work.
Smooth (no grog):
- Thin-walled functional ware
- Detailed surface decoration
- When you like a silky clay
- Small to medium pieces
Medium grog:
- Throwing larger forms (more than 5 lbs of clay)
- Hand-built sculpture or architectural work
- When you want some tooth without a lot of texture
- Outdoor work that needs to be durable
Heavy grog:
- Large-scale sculpture
- Raku firing
- Architectural work
- When strength and low shrinkage matter most
Still not sure? Work through these questions
What are you making?
- Functional dinnerware: stoneware (mid-fire or high-fire)
- Decorative sculpture: earthenware or sculpture clay, depending on size
- Fine art pottery: porcelain or white stoneware
- Large sculpture: sculpture clay with heavy grog
- Raku: raku clay
What's your skill level?
- Beginner: earthenware or a smooth stoneware
- Intermediate: any stoneware, including white stoneware
- Advanced: porcelain, high-fire stoneware or specialty clays
What kiln do you have?
- Electric: mid-fire stoneware (cone 5 to 6) or cone 6 porcelain
- Gas: high-fire stoneware (cone 9 to 10) or cone 10 porcelain
- Low-fire only: earthenware
What's your budget?
- Lower firing costs: earthenware (cone 06) or mid-fire stoneware (cone 5 to 6)
- Cost isn't a concern: any clay that suits your work
What look do you want?
- Bright glaze colors: earthenware
- Warm, earthy tones: stoneware
- Clean white surfaces: porcelain or white stoneware
- Bare clay showing: choose by the fired color you like
About Sheffield Pottery clay
We formulate and blend every clay body ourselves from carefully selected regional materials, and we check quality at every step.
It's de-aired, pugged and ready to use. You don't need to rework it. Open the bag and start.
It's consistent from batch to batch. Once you find a Sheffield clay you like, it should work the same way year after year.
We've been doing this for decades, and there are real potters on our customer service team, so you can call with questions.
Beginner, teacher or studio professional, Sheffield Pottery has a clay body for your firing range, your forming method and the kind of work you make.
Take a look at our full clay selection to find the right one for your next project.