Temmoku (also spelled tenmoku) is one of the oldest named glazes still in daily use. It is the black tea bowl glaze with rusty rims, oily spots or streaks like rabbit fur. This guide explains what makes a glaze a temmoku, why reduction matters, and what electric-kiln potters can buy instead. It is research-based, built from Digitalfire, Ceramic Arts Network and maker pages from AMACO and Coyote; we did not fire these glazes ourselves.
What is a temmoku glaze?
Digitalfire defines tenmoku as a high-temperature, reduction-fired glaze that is glossy and very dark brown or maroon, with iron oxide acting as a flux and giving it a fluid melt. Ceramic Arts Network's Techno File calls it "an iron-saturated type of Japanese glaze that is traditionally fired to cone 10." Three features mark a temmoku:
- Dark, glossy body color where the glaze is thick.
- Breaking to rust or amber where it is thin, such as rims, edges and carved lines.
- Iron crystals on the surface when cooling is slow enough, from tiny yellow specks to large rust patches.
Temmoku or tenmoku: the name and its history
The name comes from Tianmu Mountain in China, where iron-glazed bowls were used for tea at a temple; Glendale Community College calls temmoku a Japanese rendering of that place name. The best-known bowls were Jian ware from the Southern Song dynasty (1127 to 1279), conical tea bowls about 4 to 5 inches (10 to 13 cm) wide according to Wikipedia. In 1406 the Yongle Emperor sent ten Jian bowls to the shogun Ashikaga Yoshimitsu, and Seto potters later made their own temmoku, which is why the glaze is so tied to Japanese pottery. Our Japanese pottery guide places it among the other tea ceremony styles.
Famous variations have their own names:
- Hare's fur: fine brown streaks running down a black glaze. Glendale notes a thick application is essential and an iron-bearing slip underneath helps.
- Oil spot: silvery spots of iron floating on the surface. Digitalfire links the effect to gas bubbles from iron decomposition near the top of a cone 8 or hotter firing.
- Yohen (youhen): the rare iridescent spotted bowls, listed by Wikipedia among the classic types.
- Teadust and temmoku gold: matte, finely crystallized surfaces at even higher iron levels.
Iron saturation: how temmoku works
A temmoku is not a special base glaze; it is mostly a clear stoneware glaze with a lot of iron. Digitalfire's test series adds iron oxide to a transparent cone 10 reduction base and shows the progression:
| Iron oxide added | Result in cone 10 reduction (Digitalfire) |
|---|---|
| 5% | Amber glass |
| 7% | Opacity begins, tiny crystals |
| 9% | Black where thick |
| 11% | Temmoku territory |
| 13% | Iron crystallization: temmoku gold or teadust |
| 17% | Almost metallic |
At around 10 percent the iron saturates the melt and comes out of solution as crystals on cooling. Digitalfire notes that adding 5 percent calcium carbonate keeps more iron dissolved and gives a glossier, uncrystallized surface, and that a 1 to 2 percent change in calcium can matter. Cooling controls the crystals: slower cooling grows more and bigger ones, too slow gives too much crystal, and very fast cooling gives plain black. Iron specks in the clay act as seeds, so the same glaze looks different on buff stoneware and on porcelain.
Reduction temmoku: the traditional route
In a gas or wood kiln, reduction (a fuel-rich, oxygen-poor atmosphere) changes iron oxide into a form that melts more actively, which is why iron does so much at cone 10 reduction. Digitalfire stresses that temmokus are sensitive to temperature and must reach full temperature: in one kiln, a one-cone difference gave a dull, pebbly surface in one spot and a glassy metallic one in another. Cone 10 is about 2,345°F (1,285°C) on Orton's chart.
If you have access to a gas kiln, a reduction temmoku is the real thing. Our reduction firing page explains the atmosphere, and the gas vs electric kiln comparison covers what owning one involves.
Temmoku in an electric kiln
An electric kiln fires in oxidation, so you cannot get reduction iron effects the traditional way. You can still get a convincing temmoku look. Ceramic Arts Network notes that iron-saturate glazes "have recently made their way into the cone-6 oxidation world", and makers now sell glazes built for it. Expect three differences: colors lean brown and bronze rather than deep black-maroon, the break is often softer, and crystal effects depend heavily on a slow cool. Our cone 6 glazes page covers mid-fire glazes in general.
Commercial electric-kiln temmoku glazes compared
| Glaze | Cone | Surface (maker) | Food-use label | Sizes |
|---|---|---|---|---|
| AMACO PC-30 Temmoku | 5 to 6 | Satin-matte dark brown and tan, speckled, textured | Food safe (Clay-King listing of AMACO label) | Pint, gallon |
| Coyote Bronze Temmoku MBG120 | 5 to 6 | Gas-fired temmoku look on red clay; shimmering bronze on white | Not recommended for foodware (Coyote) | Pint to 3 gallon; 5 to 25 lb dry |
| Coyote Saturated Iron MBG040 | 5 to 6 | Rich, smooth deep brown; reddish when slow cooled | Coyote says test all foodware | Pint to 3 gallon; 5 to 25 lb dry |
| AMACO PC-01 Saturation Metallic | 5 to 6 | Satin metallic black, like steel | Foodsafe (The Ceramic Shop listing) | Pint |
We did not find a glaze named temmoku in Spectrum's or Mayco's cone 5 to 6 listings that we checked in October 2026; check their current charts if you prefer those brands.
AMACO PC-30 Temmoku
Picked because it is the most widely stocked electric-kiln temmoku and one of the few with a food-safe label. AMACO describes it as a textured, satin-matte dark brown and tan speckled glaze that works well under more fluid Potter's Choice glazes and as a liner for cups and bowls. Clay-King lists its fluidity as stable, so it is not the runny, glossy black of a reduction temmoku. AMACO's layering gallery shows it over glazes such as PC-31 Oatmeal, PC-29 Deep Olive Speckle and PC-21 Arctic Blue.
- Cone: 5 to 6
- Surface: satin-matte, speckled brown and tan
- Label: food safe per the AMACO label shown on Clay-King
- Sizes: pint and gallon; typically $20 to $30 a pint at US dealers in October 2026
Pros
- Stable, does not run
- Food-safe label
- Layers under fluid Potter's Choice glazes
Cons
- Satin brown rather than glossy black
- AMACO's own page does not print the cone in text
Who should skip it: potters who want the glossy black body and rust break of a classic temmoku.
See our Potter's Choice guide for the rest of the line.
Coyote Bronze Temmoku MBG120
Picked because Coyote designed it specifically to "emulate the look of a gas-fired temmoku" on red clay. On white clay Coyote says it turns a shimmering bronze, and it suggests combining it with Coyote's gloss or satin glazes. Coyote does not recommend it for foodware, because it may change color or texture with repeated food and dishwasher exposure.
- Cone: 5 to 6 (Coyote's range for all its glazes)
- Best clay: red stoneware for the temmoku look
- Label: not recommended for foodware (Coyote)
- Sizes: pint, gallon, 3 gallon; 5, 10 and 25 lb dry
Pros
- Closest electric-kiln match to a reduction temmoku
- Dramatic on red clay
- Dry sizes for dipping
Cons
- Not for food surfaces
- Costs more than most Coyote glazes
- Bronze rather than black on white clay
Who should skip it: anyone glazing the inside of mugs and bowls, or working only in white clay.
Coyote Saturated Iron MBG040
Picked as a plainer, lower-cost iron saturate. Coyote calls it "a rich, dark iron glaze" with a smooth, deep brown surface that can turn reddish, especially when slow cooled. Coyote's notes say to test all foodware.
- Cone: 5 to 6
- Surface: smooth deep brown; reddish with a slow cool
- Label: Coyote says test all foodware
- Sizes: pint to 3 gallon; 5 to 25 lb dry
Pros
- Classic dark iron look
- Responds to slow cooling
- Budget-friendly for Coyote
Cons
- Less crystal and break than a true temmoku
- No food-safe label
Who should skip it: potters whose kiln controller cannot run a slow cool, since that is where the color develops.
Metallic and oil spot alternatives
AMACO's PC-01 Saturation Metallic (satin black) and PC-02 Saturation Gold (bronze) imitate iron-saturate surfaces; The Ceramic Shop lists both as foodsafe, restricted from use for grades K to 6, and says to apply three thick coats with room at the foot for movement. For oil spots at cone 6, Coyote's Texas Two-Step system pairs an undercoat with an overcoat that pulls apart into spots; our Coyote glazes page covers it.
Applying temmoku and stopping runs
Thickness decides the look. Thin coats give amber and rust; thick coats give black and crystals, but iron-rich glazes melt fluidly. Digitalfire warns that runs can glue pieces to shelves and suggests a catcher glaze band of 5 to 10 mm. Practical rules:
- Leave the bottom 1/4 to 1/2 inch of the pot bare and wax the foot.
- Fire new glazes on a cookie or waste bisque under the pot until you know how they move.
- Coat kiln shelves with kiln wash.
- Glaze over texture and sharp edges to make the most of the break.
- If your controller allows, try a slow cool through the crystal range and compare it with a normal firing on test tiles.
Mixing your own temmoku
Digitalfire describes the simplest route as about 10 percent iron oxide added to a transparent cone 10 reduction base, and notes that Alberta Slip needs only about 1 to 2 percent added iron to become a temmoku. For cone 6 oxidation, use a recipe written and tested for oxidation rather than adapting a cone 10 one. Our planned glaze recipes for beginners page covers mixing.
Mixing glaze from raw materials means handling fine silica, iron oxide and other powders. Wear a NIOSH-approved respirator, mix and clean wet, and read the Safety Data Sheet for every material.
Food safety
We quote maker labels only. AMACO's PC-30 carries a food-safe label as shown on Clay-King's listing; Coyote does not recommend Bronze Temmoku for foodware and says to test all foodware for its other glazes. A maker label is not a promise about your pot: results depend on firing to the stated cone, the clay, thickness and layering. Heavily crystallized or metallic surfaces can also be harder to clean. See our planned food safe glaze guide for testing options.
Common mistakes
- Applying too thin. A thin temmoku fires muddy amber with no black.
- Under-firing. Iron saturates are sensitive; place witness cones near the pots.
- Fast cooling. Crystals and red tones need time; a crash cool gives flat black or brown.
- Glazing to the foot. Fluid iron glazes run onto shelves.
- Expecting reduction results in oxidation. Choose a glaze written for your kiln.
What you need
A temmoku in an electric kiln needs a kiln that reaches cone 6 reliably, ideally with a programmable controller for a slow cool. If you are still choosing one, start with our best kilns for home pottery.
Sources: Digitalfire glossary entries "Tenmoku" and "Oil-spot glaze"; Ceramic Arts Network, Ceramics Monthly "Techno File: Tenmoku to Tomato Red"; Wikipedia, "Tenmoku"; Glendale Community College, hare's fur temmoku bowl notes; AMACO shop page for PC-30 Temmoku and AMACO layering gallery; Clay-King PC-30 Temmoku listing; The Ceramic Shop listings for PC-01 Saturation Metallic and PC-02 Saturation Gold; Coyote Clay and Color pages for Bronze Temmoku, Saturated Iron, Texas Two-Step Oilspots, cone 6 glaze list and Safety (food safety); Krueger Pottery Spectrum 1100 listing; Ahrefs SERP data for "temmoku glaze". Specs checked October 2026.