The craft brewers use natural ingredients as much as possible and with the introduction of "brewery agriculture" also using barley and hops, from the territory of their membership. The beer is produced mainly with the barley malt and / or with the wheat malt (and in some cases also with other malted cereals), basic elements, to which are added hops, yeast and water. At this point the beer is ready for drinking but has a limited duration in time. To enhance the conservation, in the industrial production, the product is subjected to certain treatments such as pasteurization and filtering. They are thus inactivated microorganisms contained in the yeast and filtered the drink, then adding of preservatives and stabilizing additives. After this treatment the product can be handled and stored without any problem. The beers produced by industrial techniques, therefore, differ substantially from those craft to an organoleptic test. The presence of active yeast also makes the latter a living food that evolves over time. If the type of beer allows, you can also aged in the cellar for a few years. The phenomenon of craft breweries, born in the United States and is a rediscovery that occurs from the eighties, the so-called "American Renaissance", where many European immigrants, they manage to keep alive some old European products that otherwise would have missed. Even in Europe and in Italy this phenomenon is emerging that promises to offer high quality handicraft products.