Fuller's Earth also known as Multani mitti is a clay like substance that is composed of aluminium magnesium silicate. While Bentonite clay, also known as Montmorillonite clay, is an absorbent aluminium phyllosilicate clay. Both of these are very similar in the sense that they contain many of the same components. Fuller's earth also contains bentonites that is formed of ash taken from volcanoes. That being said Multani mitti leaves a strange off-flavor in the wine. Hence Multani Mitti is used in face pack, mud bath and other external purposes only. Please don't add multani Mitti to wine.
Bentonite clay and fuller's earth are both highly absorbent in nature and have similar skin benefits and cleansing properties. But bentonite clay is has more healing properties as compared to fuller's earth. It is also consumed as an antidote for toxins in body. However fuller's earth is not considered suitable for consumption.