After how many months does lactic acid fermentation occur post-primary fermentation in lambics?

Lactic acid fermentation in lambics typically occurs after the primary fermentation, which is usually around three to four months into the fermentation process. During the initial stages of fermentation, wild yeast, particularly Brettanomyces, and lactic acid bacteria like Lactobacillus play crucial roles. After primary fermentation wraps up—with the initial sugars being converted into alcohol—these microorganisms continue to work, leading to lactic acid fermentation.

The extended aging process that occurs in lambics is essential for the development of the complex flavors and aromas characteristic of these beers. It is during this period that lactic acid bacteria contribute to the sourness through lactic acid production. Therefore, the timeframe of three to four months accurately reflects the ongoing fermentation process where lactic acid is produced, which begins shortly after the primary fermentation concludes.

In contrast, fermentation processes occurring at shorter durations would not allow for adequate development of these sour flavors or for the bacteria to effectively contribute to the beer's profile. Longer timeframes might suggest a stage where other fermentation characteristics begin to dominate, deviating from the typical timeline associated with lambic production.