Glaze is the glass-like coating that gives fired pottery its color, texture, and finish, and for functional pieces, a food-safe surface. Understanding the basics of how glaze works, the difference between glaze types, and how to apply it will help you make better decisions in the studio and get results you’re proud of.
If you’re new to ceramics, glazing can feel like the most mysterious part of the process. You apply what looks like a dull, chalky liquid to your bisqueware, slide it into the kiln, and hope for the best. Then you open that kiln door and find something completely different from what you expected, or, if you’re lucky, something even better.
The good news is that glaze doesn’t have to feel like a guessing game. Once you understand a few basic concepts (what glaze is, how it behaves, and what the different types do), you’ll have a much clearer sense of how to approach the decorating phase with intention rather than just crossing your fingers.
What Is Ceramic Glaze?
Glaze is a glass-forming coating that’s applied to bisqueware (pottery that has been fired once but not yet decorated) and then fired a second time in the kiln. During that firing, the glaze melts, flows slightly, and fuses with the clay body beneath it, forming a durable, glassy surface.
That surface does several things at once. It makes the piece more durable. It seals porous clay bodies, allowing them to hold food and liquids safely. It adds color, texture, and finish. And it gives you, as the potter, a huge range of expressive options, from clean, bright solids to rich, layered, unpredictable surfaces that look different every time.
The raw ingredients that make up a glaze include silica (the glass-forming material), flux (which lowers the melting temperature so the glaze fuses properly), and alumina (which adds stability and prevents the glaze from running too much). Commercial glazes have all of these balanced and ready to use straight from the container, which is why they’re a great starting point for beginners.
Glaze vs. Underglaze vs. Paint: What’s the Difference?
Before going further, it’s worth clearing up a point that trips up many beginners: glaze, underglaze, and paint are three different things, used at different stages and for different purposes.
Glaze is applied to bisqueware and fired to create a glass-like surface. It’s the final coating on most ceramic pieces and is what makes functional pottery food-safe when used correctly.
Underglaze is a color product applied before the top glaze. It can go on leather-hard clay, bone-dry greenware, or bisqueware, and it requires a clear or transparent glaze to seal the surface and bring out its true color. Underglazes are formulated to behave more predictably than top glazes: colors stay where you put them, they don’t run or bleed, and they’re mixable like paint. They’re an excellent choice for detailed work, images, lettering, or any design where precision matters.
Paint (acrylics, oils, watercolors) is a cold-surface technique that doesn’t require firing. Painted pieces need a sealer rather than a kiln. The resulting surface is less durable than fired glaze and isn’t as food-safe. That said, cold-surface paints are a perfectly valid option for decorative pieces that won’t see the inside of a dishwasher.
For most pottery, the approach is: underglaze for color and detail work, clear or transparent glaze on top to seal and add sheen.
Glaze Finishes: Gloss, Satin, and Matte
Commercial glazes are generally categorized by their finish after firing. Understanding these three categories will help you choose a glaze that matches the look you’re after.
Gloss glazes fire to a shiny, reflective surface. They’re the most popular choice for functional pottery (mugs, bowls, plates) because their smooth surfaces are easy to clean. Gloss glazes tend to show color vibrantly and are generally very food-safe, making them the go-to for any piece that will hold food or drink. If you’re unsure where to start, a classic gloss glaze is rarely the wrong answer.
Matte glazes fire to a flat, non-reflective surface that can range from smooth and velvety to slightly rough or stony to the touch. Matte surfaces have a quiet, earthy quality that works beautifully on sculptural pieces and hand-built forms. They can be slightly more porous than gloss surfaces, so if you’re using a matte glaze on functional ware, check the manufacturer’s label to confirm it’s food-safe.
Satin glazes sit between gloss and matte, with a low, soft sheen that’s smooth to the touch without being reflective. Many potters find the satin finish the most versatile because it looks polished without drawing attention to itself. It works well on both functional and decorative pieces.
No one finish is “better” than the others. The right choice depends on the piece, the clay body, and the look you’re going for.
Understanding Firing Ranges
One of the most important things to know about glaze, and one that beginners often overlook, is that not all glazes work at all temperatures. Glazes are formulated for specific firing ranges, and using a glaze outside its intended range will produce poor results at best and a kiln disaster at worst.
Firing ranges are described using a cone system, where the cone number corresponds to a target temperature. Here’s a basic overview:
Low fire (Cone 06–Cone 04, approximately 1828–1945°F) is the most accessible range for beginners. Low-fire glazes tend to be bright and vivid. If you’re working with earthenware clay in a smaller entry-level kiln, low-fire glazes are your category.
Mid-range (Cone 4–Cone 7, approximately 2124–2264°F) is the most common range for studio potters working in electric kilns. Cone 6 in particular has become something of a standard for both stoneware and bisqueware. Mid-fire glazes offer a wide variety of finishes and are well represented by major brands such as Amaco, Mayco, Coyote, and Spectrum.
High fire (Cone 8–Cone 10, approximately 2300–2381°F) requires a kiln capable of reaching very high temperatures. High-fire glazes tend to have a depth and complexity, particularly in reduction kilns, that’s harder to achieve at lower temperatures, and many experienced potters work exclusively in this range.
The simplest rule: match your glaze to your clay body and your kiln. Check what cone your clay fires to, confirm your kiln can reach that temperature, and then shop glazes in that range. The packaging on any commercial glaze will tell you its intended firing range.
How to Apply Glaze
There are four main methods for applying glaze to bisqueware, each with its own advantages depending on the piece and the effect you want.
Brushing is the most common approach for beginners and is well-suited to detailed or intricate work. Apply two to three full, flowing coats, allowing each coat to dry completely before adding the next. Brush strokes can show in the finished piece if you’re not careful, but with practice, you’ll develop a consistent, even touch. Most commercial glazes are formulated to level out during firing and minimize brush marks.
Dipping involves submerging the piece directly into a container of glaze, then pulling it out and letting the excess drip off. It produces a very even, consistent coat and is especially practical for production potters glazing large quantities of similar pieces. You’ll need enough glaze volume to fully submerge the piece, which means dipping works best once you’ve built up a decent studio inventory of glaze.
Pouring is useful for the interior of bowls, vases, and other vessels. You pour glaze into the piece, swirl it to evenly coat the interior, and then pour the excess back into the container. For the exterior, glaze can be poured over the piece while it sits on a rack, catching the runoff below.
Spraying uses an airbrush or spray gun to apply glaze in thin, even layers. It produces exceptionally smooth, consistent results and is popular for large pieces or complex layered effects. Spraying does require some additional equipment and should always be done with proper respiratory protection, since you’re putting glaze material into the air.
Regardless of method, always make sure to wipe any glaze from the bottom of the piece before firing. Glaze that comes in contact with the kiln shelf during firing will melt and bond the two together permanently, which is a bad day for everyone involved.
A Few Things to Know Before Your First Glaze Fire
Wet glaze looks nothing like fired glaze
The chalky, dull appearance of the glaze in the bucket is completely different from its fired result. This dullness is normal. If you’re working with an unfamiliar glaze, fire a test tile first so you know what to expect before committing to a finished piece.
Glaze can move
During firing, glaze melts and flows. Some glazes are more fluid than others. If you’ve applied glaze heavily or chosen a particularly fluid glaze, there’s a real chance it will run toward the bottom of your piece. Keep the bottom inch of your piece unglazed as a buffer zone, and always know your glaze’s tendencies before firing.
Color shifts are normal
A glaze that looks pale pink in the jar might fire to a deep burgundy. Glaze color is the result of metal oxides reacting to heat, not pigment sitting on a surface. Again, test tiles are your friend.
Most glazes are food-safe, but not all
Read the label carefully, particularly with specialty glazes like lusters, raku glazes, and some decorative finishes. When in doubt, reserve those glazes for decorative pieces only.
Choosing Your First Glazes
For most beginners, the best advice is to start simple: choose a well-reviewed brushing glaze in the correct cone range for your clay body, pick a handful of colors you love, and get to know how they behave before expanding your palette. Amaco’s Potter’s Choice series and Velvet Underglazes, Mayco’s Stroke & Coat line, and Coyote’s commercial glazes are all popular, well-documented choices with reliable results and plenty of community support.
As you get more comfortable, you’ll naturally start experimenting: testing combinations, trying different application methods, and seeking out glazes with more complex effects. That’s where things start to get really interesting.
Still figuring out where to start? The Clay-King team is here to help.
We’ve spent a lot of time thinking about glazes, and we love matching potters to the right products for their projects and skill levels. Give us a call at 888-838-3625 or email us at info@clay-king.com, and we’ll be happy to point you in the right direction.
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