Along with climate and grape variety, this is one of the most important factors influencing wine quality. The different soil types have developed over millions of years through physical and chemical weathering of rocks and through humification of organic matter. In physical weathering, natural forces such as wind, water, heat, cold and frost initially cause the mechanical disintegration of the rock formations into clods and gravel. Strong temperature opposites, frictional and shear forces as well as frost blasting by frozen water play an important role in this process. Chemical weathering processes such as oxidation, dissolution processes and acid attacks attack the mineral lattice structure of the rocks. In the process, easily water-soluble minerals such as carbonates (inorganic salts and organic esters of carbonic acid) and sulphates are dissolved first, and the rock slowly decomposes into grit, sand, silt or clay. Every rock, even the hardest granite or quartz will eventually decompose to dust, even if it takes many millions of years.
The glossary is a monumental achievement and one of the most important contributions to wine knowledge. Of all the encyclopaedias I use on the subject of wine, it is by far the most important. That was the case ten years ago and it hasn't changed since.Andreas Essl