As in gardening, the selection of good seed ensures a good wine. Wild yeasts are found on almost all fruit, but these generally produce a wine which is inferior in flavor and of a lower alcohol content than wines produced by select strains of yeast. Just as there are weeds in the garden, so there are weeds in wines. There are microorganisms the feed on alcohol and cause a poor flavor. Vinegar bacilli will change sugar to vinegar.
Molds give a stale flavor.
To prevent these unwelcome intruders, cleanliness is the only answer. This is inexpensive and does not contribute a taste of its own. Baking soda is fairly effective if given time to work. Either of these agents will remove odors and flavors from the containers. If soap or detergents are used, the containers must be carefully rinsed.