EM ceramics: uses, manufacturer claims, and what to really make of them

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Gray or pink beads in the pitcher, a ring at the bottom of the water trough, a tube in the rain barrel, powder in paint or in the vegetable garden: EM ceramics are a category of their own in the world of effective microorganisms. They are also the products surrounded by the most surprising promises.

We sell them, and many of our customers like them. This guide explains how they are made, what the manufacturer says about them, what the science says, and how to use them with the right expectations.

How EM ceramics are made

The principle is always the same. A clay, often Japanese Kibushi clay, is fermented with effective microorganisms, then shaped and fired in a kiln. According to the technical data sheets, the firing temperature is what sets the products apart:

• around 2,190–2,370 °F (1,200–1,300 °C) for the gray beads and balls, rings, and tubes: the ceramic is dense and very durable;
• around 1,470–1,650 °F (800–900 °C) for the pink beads: the ceramic is more porous and more fragile, and is for cold water only.

One point deserves to be stated clearly, and the manufacturer itself acknowledges it: no microorganism survives that kind of firing. An EM ceramic is an inert mineral object. It contains no living bacteria and does not inoculate the water.

The range and its uses

• Gray EM ceramic beads and balls: pitcher, kettle, coffee maker, washing machine, dishwasher, vase. They last more than ten years as long as they don't break.
• Pink EM ceramic beads: cold water only (pitcher, vase, aquarium, pond), to be replaced every six months.
• The ring and the Maxi Tube: a single piece for a large container, such as a water trough, a bathtub, or a rain barrel, which calls for the 35 mm ceramic Maxi Tube.
• Figurines: for the pitcher, cooking water, or the bath.
• Powders: Cera Boost powder for soil, mulch, or bokashi, and a fine powder to mix into paint or plaster.

What the manufacturer claims

According to the manufacturer, EM ceramics retain “information” from the microorganisms after firing and act on water through a “resonance principle.” They are said to improve the structure and taste of water, reduce scale buildup and oxidation, keep food and cut flowers fresh longer, and, in the case of certain powders, reduce formaldehyde emissions from paint. Some product descriptions even go so far as to mention protection against electromagnetic waves.

We report these claims so you know what is being said. We do not endorse them.

What the science says

To date, we have found no independent study showing any effect of EM ceramics on water, food, or health. The few assessments available all point in the same direction:

• In the field, trials running over several years spread EM ceramic at 134 lb per acre (150 kg per hectare): no gain in yield, and only a slight increase in the protein content of barley, an effect considered rather undesirable.
• The available critical reviews consider the claimed effects of the ceramics, on soil as well as on water, inconceivable given current scientific knowledge.
• The notions of “information” or “resonance” passed on to water by an object do not match any known mechanism in physics or chemistry. The same goes for the “structure” of water, which keeps no lasting organization.

The formaldehyde case

The manufacturer cites a test: 0.35 oz (10 g) of ceramic placed in a 15.9-gallon (60-liter) tank reportedly reduced formaldehyde by 90% in 24 hours. This test has not been published in a scientific journal, no control tank without ceramic is described, and the starting concentration was hundreds of times higher than in a home. A porous ceramic can hold some gases on its surface, as many mineral materials do: this is an ordinary physical phenomenon that has nothing to do with microorganisms. A patent, often highlighted, protects an invention but does not prove that it works.

Did you know?

In an uncovered pitcher, the chlorine taste of tap water fades on its own within a few hours, because the chlorine evaporates. Part of the improvement in taste credited to the beads simply comes from letting the water stand in the open air.

What to make of them: our advice

EM ceramics are durable objects made from natural material, and they are pleasant to use. Many of our customers enjoy this small daily ritual and find their water more enjoyable. We simply recommend using them for what they are, without expecting them to play a role they can't fulfill.

• It is not a filter. Water that isn't safe to drink stays unsafe with ceramics. Water from a rain barrel does not become drinkable.
• It is not a water softener. For very hard water, a water softener remains the recognized solution.
• It is not a treatment: not for swimming pool or hot tub water, not for plants, and not for animals. Cera Boost is a fine mineral powder, not a protection against disease; if an animal has a wound, call your veterinarian.
• Hygiene and safety: throw away any cracked or broken bead, keep small pieces out of the reach of young children, and do not use the pink beads in hot water.

Emy's tip

Rinse your beads in clean water before using them for the first time. After that, every three months, scrub the gray beads, soak them overnight in diluted white vinegar, rinse them, and boil them for 20 minutes. Replace the pink beads every six months.

If you're looking for measurable effects on a pond, soil, or animal bedding, turn instead to liquid EM products, used with the same caution: see, for example, our guide Caring for a garden pond or wildlife pond with EM. And for swimming pools, read our guide EM and swimming pools first.

Why we offer them

We sell these ceramics because our customers ask for them, because they are carefully made, and because they last for years. But we would rather tell you what has been proven and what hasn't than let you buy a promise. It's the same approach we take throughout the “Going further” section of this guide, summed up in our guide What the science says about EM. The rules governing how these objects may be presented are explained in the guide EM and regulations.

Key takeaways

An EM ceramic is an object made of clay that has been fermented and then fired, with no living microorganisms. Its effects on water are unproven manufacturer claims. Use it as a pleasant, durable object, never as a filter, a water softener, or a treatment.

In summary

EM ceramics are made from clay fermented with EM, then fired at 1,470 to 2,370 °F (800 to 1,300 °C): they no longer contain any living microorganisms. The manufacturer credits them with effects on water, scale buildup, food storage, and indoor air, but no independent study confirms these effects, and the mechanisms put forward don't match anything known to science. You can use them as durable, pleasant objects, well maintained, without expecting them to act as a filter, a water softener, or a treatment.

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Other topics in the guide

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