Description
Propionibacteria ferment lactate at elevated temperatures, producing CO₂ bubbles that form characteristic holes in Swiss-style cheeses.
Technical
Propionibacterium freudenreichii metabolizes lactate into propionate, acetate, and CO₂ via the Wood-Werkman cycle, with gas formation occurring optimally between 50-55°C during the 'warm room' phase of cheesemaking.
Culinary Significance
Creates the signature 'eyes' in Emmental and Appenzeller cheeses while developing nutty, sweet flavor compounds through controlled gas expansion in the cheese matrix.
Science
Primary Reaction
3 Lactate → 2 Propionate + 1 Acetate + 1 CO₂ + 1 H₂O
Parameters
Temperature
52°C optimal
20°C to 55°C range
Time
8-12 weeks
3 weeks – 6 months
Equipment
Copper vats (traditional)Temperature-controlled aging roomsCheese harp for curd cutting