Difference between Miriams Earthen Cookware’s pure clay pots and all other cooking pottery: ceramic, porcelain, stoneware, flame ware, earthenware


Ceramic/porcelain, stoneware pots and pans: From making toilets to tiles to cooking pots, the ceramic material has been used for several decades and is loosely called ‘clay’ because of its elasticity that resembles natural clay.  The ceramic/porcelain raw material contains only about 5-7% natural clay, the other 95% are chemicals, oxides (obtained through fracking) and other inorganic substances obtained from deep within the earth and processed in an environmentally detrimental manner.   A typical mixture could contain over 75 different chemicals, some of which are listed here: Chemicals, toxins, oxides and inorganic substances in ceramics.

The unique combination of chemicals depends on the final product and is usually a well kept secret.  For example, if being made into a cooking pot, the chemical petalite is added in a certain percentage (this is an ore of lithium) to control thermal shrinkage.  Another formula may include chemicals for the ware to withstand very high firing temperature to make into tiles, toilets etc., and so may be called porcelain. Because it’s a combination of elements sourced from different origins this material has to be fired to very high temperature to fuse all these foreign elements together.  Because of the presence of dangerous chemicals this ware always needs to be glazed.

Flame ware pots and pans: Flame ware is another name given to the ceramic raw material that has specific chemicals added to withstand heat.  This raw material may or may not contain any real, natural clay.  And typically has some extremely toxic chemicals including petalite, an ore of lithium. Because of the presence of dangerous chemicals this ware also always needs to be glazed before using for food.

Stoneware pots and pans: have a higher percentage of natural clay, typically up to 40% and the rest of the raw material is a combination of chemicals, oxides and some toxic additives.  Because they have a greater percentage of natural clay, their firing temperature is less than ceramics or porcelain. Because of the presence of chemicals this ware also needs to be glazed before being used for food.

Earthenware or terracotta pots and pans: Earthenware or terracotta is a term interchangeably used for pots and pans made from a combination of low fire natural clay and may contain additives.  The additives are chemicals added to the clay to increase elasticity, for uniformity in firing, and to add color to the fired items. Chemicals and additives are also added for ease of processing and to increase manufacturing speed.  An example of such a chemical is a deflocculant like sodium silicate or Darvan 811 or Darvan 7, these chemicals are added to increase homogeneity and for better suspension and reduce or limit the percentage of water allowing faster drying times. Another example of a chemical added is Iron Oxide, to yield a deep, dark red to the ware. Besides the fact that the raw material could have chemicals, this clay is also not tested and so may contain natural contaminants like mica or contaminants that are present because of careless disposal of industrial waste or farming. These contaminants could include lead, cadmium and/or arsenic.  Since its only economical for potters who use this clay to harvest what is locally available, it in most cases is secondary clay that has different natural contaminants also (it’s not just clay). Earthenware/terracotta may or may not be glazed.

Pure-clay pots and pans: are pots and pans made from 100% all natural, primary clay – i.e. clay that is more elastic than earthenware or terracotta because it has NO contaminants.  It only contains its natural ingredients which are nutrients like Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg) and Micro-nutrients: Boron (B), Manganese (Mn), Zinc (Zn), Iron (Fe) etc.  Miriams Earthen Cookware goes one step further to make sure and let their customers know they only use pure clay by scientifically testing their clay and they publish the test results as well. We are happy to be the only company in the world to do this. This is what makes their pots made from 100% pure-clay the best and healthiest for cooking. Miriams Earthen Cookware pots/pans are pots and pans made using only 100% pure-clay, no other additives or chemicals are used and they’re unglazed. Because pure-clay is one single entity used as it is found in nature and all the nutrients are already bound together as one, it does not require high firing temperatures.  The firing in this case is done only to completely eliminate chemically bound water (H2O) and fuse these naturally bound elements.

Glaze is typically a liquid that is a combination of different chemicals, oxides and metallic and non-metallic substances.  This list contains some of the ingredients in glazes.  It is typically used to cover ware made with ceramic, porcelain, stoneware materials.  It is also used for earthenware and stoneware.