This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Beurrée d’nièr beurre black butter on apple butter cake. Apple butter is a highly concentrated form of apple sauce produced by long, slow cooking of apples with cider or water to a point where the sugar in the apples caramelizes, turning the apple butter a deep brown.
Typically, the jars are sterilized before packaging to ensure no harmful microorganisms or bacteria will infect the product, causing it to spoil. Ideally, jars are sterilized using a combination of high temperature heating and ensuring a tight seal. Apples are a high acid food, with a pH below 4. Therefore, the apple butter can be placed in hot jars without chances of compromising quality of the product. The main sources of spoilage, molds, yeasts and enzymes, are killed at the temperatures reached in the hot water bath during the sterilization process for cans and jars. Freezing jars of apple butter can help to maintain quality and inhibit bacterial growth. This storage method does not destroy pre-existing microorganisms that may be present in the product, so it is important to be wary when consuming previously frozen product.
Applying high temperatures over a specified period of time can not only aid in the sterilization of the jars or cans used in packaging, but it can help maximize the storage time of the apple butter or other products. Boiling the jars will remove the oxygen remaining in the jar, which forms a tight seal between the lid and the rim. Similar to the boiling process, vacuum sealing jars or cans of apple butter can remove remaining oxygen in the jar, forming a tight seal. The vacuuming process can be done in both a large-scale factory manner or at home with a mechanical vacuum sealer. Special devices, such as a vacuum pack sealer, can be fitted with specific jar attachments to fit over the lid of a jar and create a secure fit. Apple butter does not require sterilization at extremely high temperatures to reach optimum storage and maintain quality, so the pressure canning process is not typically used for this product.