Purpose and key benefit Lightweight fermenting lid with a glass fermentation weight designed for widemouth mason jars. Keeps vegetables and other foods submerged to create and maintain the lowoxygen environment required for reliable lactic acid fermentation. Why you need it Prevents oxygen from entering the jar and contaminating ferments, reducing surface yeast and mold growth. Creates consistent, predictable conditions so you get a proper lactic acid ferment every time. Compact and portable: easy to use, remove, and store between batches. Main features Compatibility: Designed to fit widemouth mason jars and fill the jar space so ferments stay submerged. Material and design: Glass fermentation weight combined with a lightweight fermenting lid to provide a stable, foodsafe pressing surface. Function and performance: The weight squeezes the jar space and holds ingredients below the brine, helping maintain anaerobic (lowoxygen) conditions for lactic acid fermentation. Ease of use: Simple to place inside the jar and cover—no complex setup. Easy to clean and store. How it solves common problems Keeps produce pressed under brine so air pockets do not form, minimizing contamination and offflavors. Offers a reliable method for maintaining the jar environment without continuous monitoring or elaborate equipment. Lightweight lid and compact glass weight make handling and storing finished batches convenient. Typical use scenarios Sauerkraut: Place shredded cabbage, seasonings, and brine in a widemouth mason jar; set the glass weight on to keep cabbage submerged throughout fermentation. Kimchi and pickled vegetables: Use the weight and lid to press down mixed vegetables so the brine covers all pieces, promoting even lactic acid development and preventing surface spoilage. Smallbatch ferment experiments: Ideal for trying recipes or fermenting small quantities where you need a reliable way to keep ingredients under brine in a widemouth jar. Care and tips Place the glass weight on of the packed ingredients and secure the fermenting lid as needed for your jar system. Clean the weight and lid after each use; glass components are simple to wash and inspect for residue. Use with appropriate brine recipes and temperatures for lactic acid fermentation results. This fermenting lid and glass weight combination delivers a simple, effective way to achieve consistent, lowoxygen conditions in your widemouth mason jars for successful lactic acid ferments.