Before milling, fruit should be washed to remove soil, dead insects, leaves, stones, and rotten apples. It is fortunate that healthy apples float in water (pears don't!), thus providing an easy way to wash and clean the fruit. Clean water should be used to wash each batch of fruit - if the water is recycled, the dirt is recycled too! Don't be afraid of washing away the yeast - you won't! It is a popular fallacy that desirable fermenting yeasts are present on the fruit skin. There are indeed some types of yeast on the skin and in fact there can be up to 45,000 yeast cells per gram of fruit actually inside the apple itself, which get there through the open eye (where the flower petals once were). However, scientific study has shown that these yeasts (species such as Kloeckera and Candida) have only weak fermenting power and they soon die in more than a couple of percent of alcohol. They are not the Saccharomyces yeasts which are required for the successful completion of fermentation.
In a traditional cider-making operation where no yeast is apparently used, the inoculum resides on the press racks, the cloths, the vats, or even on the walls and ceiling. It persists from season to season but virtually none of it comes from the apples. Wild Saccharomyces yeasts are not very common, so this inoculum can take several years to build up but, once established, it can determine the 'house flavour' of a particular product. It is largely a matter of luck whether this flavour is desirable or not. We return to the subject of yeasts in a later section.