The gasket is the only component in a Tri-Clover connection responsible for sealing, and its material determines what temperatures, chemicals, and pressures the joint can handle. Choosing the wrong material risks leaks, premature degradation, or product contamination in food and beverage applications.
Silicone
Silicone is the default choice for most food and beverage applications. It's flexible, FDA-compliant, and handles temperatures from roughly -60°C to 200°C with good resistance to alcohols, mild acids, and most cleaning products. It's also non-reactive, meaning it won't impart taste or odour to the product.
Silicone doesn't perform well with petroleum-based oils, aromatic solvents, or prolonged high-concentration steam exposure. For most brewing and general food processing applications, it remains the right choice.
PTFE
PTFE is chemically resistant to almost everything, handling strong acids, solvents, aggressive sanitizers, and virtually any fluid encountered in food, beverage, or laboratory settings across a temperature range of -200°C to 260°C. It's the right choice when handling fluids that would degrade silicone, or when the highest level of chemical resistance is required for a sensitive product.
The tradeoff is stiffness. PTFE requires more clamping force to seal, is less forgiving of minor ferrule face imperfections, and can take a permanent set under sustained compression, gradually reducing sealing force over time.
EPDM
EPDM's primary strength is steam and CIP resistance. It handles temperatures up to around 150°C in steam service and holds up well against the hot caustic and acid solutions that cycle through food processing systems regularly, outlasting silicone in these conditions.