Is it normal for the pear wine I brewed to turn black

The blackening of pears in pear wine is a normal phenomenon, mainly related to factors such as oxidation reaction, fermentation process, sugar conversion, fruit acid action, and container material.

1. Oxidation Reaction

When pear meat is exposed to air, the polyphenolic substances in it will undergo enzymatic browning reaction upon contact with oxygen, resulting in a darker color. This phenomenon is similar to the discoloration of an apple after being cut open, and belongs to a natural chemical reaction. If the sealing is not tight or stirring is frequent during the brewing process, it will accelerate the oxidation process.

2. Fermentation Process

During alcohol fermentation, yeast breaks down sugar in pears, while producing small amounts of organic acids and pigment precursors. As the fermentation time prolongs, the cell structure of pear flesh is gradually disrupted, and intracellular pigments are released and come into contact with the wine, possibly forming dark complexes.

3. Sugar Conversion

Pears contain high levels of fructose and sorbitol, which undergo caramelization during fermentation. When the liquor is in a high temperature environment, sugar substances undergo Maillard reaction, producing brown substances such as blackcurrant, which may adhere to the surface of pear flesh.

4. Effect of fruit acid

Organic acids such as tartaric acid and malic acid in pear wine will undergo color reaction with anthocyanins in pear skin. Especially when using red pear varieties, acidic environments can cause changes in anthocyanin structure, resulting in a purple black color tone. This phenomenon will gradually become apparent during the aging process.

5. Container Material

If iron or copper utensils are used to process pear flesh, metal ions will combine with tannins in the pear to form dark colored complexes. Although glass or ceramic containers are not prone to this reaction, long-term soaking may still cause the pear flesh to darken in color. When making pear wine, you can choose fresh pears with moderate maturity, peel them and quickly put them into the jar to reduce oxidation. Use glass containers and strictly control the fermentation temperature, regularly check the condition of the liquor. If the wine has no odor and the pear flesh only changes color, it usually does not affect the safety of drinking. When stored, it should be sealed away from light and kept at a temperature of 15-20 degrees Celsius. Filter and remove fruit residue before consumption, and the flavor will be better after refrigeration. For individuals with gastrointestinal sensitivity, it is recommended to try a small amount to confirm tolerance before drinking in moderation.