Weck 743 Mold Jar Transparent Glass Food Storage Containers with Airtight Lids (3/4 Liter Tall Jars, Set of 4)

The Weck 743 has the strongest lid material profile in the category — glass lid, natural rubber gasket, stainless steel clamps, zero plastic anywhere. The jar body is soda-lime glass (score 9, chemically inert but lower thermal shock tolerance than borosilicate).

However, a confirmed active Prop 65 warning with lead found in the exterior glass glaze at 142–159 ppm disqualifies this product from R3 recommendations. Weck contests that this lead cannot migrate into food, but has not published migration test results to support that position.

Weck claims FDA and European Food Safety Authority compliance but has not published independent lab testing results. The absence of published lead migration test results is directly relevant to the Prop 65 disqualification. Until Weck releases migration data showing the food-contact interior is safe, this product cannot be recommended.

The Weck 743 is fundamentally a canning jar — designed for water-bath canning, which is a more demanding preservation standard than everyday refrigerator storage. The clamp + gasket system seals well for fridge storage.