water keeps leaking out from under the lid of my pressure canner once it gets hot, before i even put the weight on, is that normal?

Diagnosis

A steady leak of water or steam from the rim of the lid before the pressure regulator (weight) is applied is an indication of a failure in the primary airtight seal. In a Presto 01755, this typically occurs because the gasket is not creating a uniform compression seal against the aluminum rim of the pot. While a tiny amount of "burping" is common as air escapes during the initial heat-up, a visible stream of water or constant hissing steam indicates that the internal pressure is escaping prematurely. This failure usually stems from one of three root causes: a displaced or degraded gasket, debris trapped in the sealing groove, or an unevenly tightened lid. Because the Presto 01755 uses a manual locking mechanism, if the lid is not rotated to the fully locked position, the gasket will not be compressed enough to hold the pressure. You can confirm the leak by observing the rim; if you see water bubbling out or steam escaping from a specific point on the circumference of the lid rather than the vent pipe, the seal is compromised.

How to Fix It

To resolve the leak and ensure a safe, pressurized environment for canning, follow these precise steps:

1. Turn off the heat source and allow the canner to cool completely. Never attempt to open a pressurized lid, as this can cause a violent release of steam and contents.
2. Carefully lift the lid and remove the silicone gasket from the groove. Inspect the gasket for any cracks, tears, or "flattening" (where the rubber has lost its elasticity and no longer bounces back).
3. Use a damp cloth and a soft brush to clean the entire circumference of the lid's sealing groove. Even a small piece of food debris or a grain of salt trapped in the groove can create a gap large enough for steam to escape.
4. Inspect the rim of the pot itself. Ensure there are no dents or scratches on the top edge of the aluminum where the gasket meets the metal.
5. Reinstall the gasket, ensuring it is seated flat in the groove. Press firmly around the entire circle to make sure there are no twists or pinched sections.
6. Place the lid on the pot and rotate it clockwise to lock. Ensure the lid is fully seated and that the locking tabs are completely engaged. Do not over-tighten to the point of warping the aluminum, but ensure it is snug.
7. Refill the pot with the required amount of water (typically 2-3 inches) and bring it to a boil again to test the seal before adding the weight.

If That Didn't Work

• Replace the Gasket: If the gasket looks intact but still leaks, the silicone may have hardened over time. Purchase a genuine Presto replacement gasket specifically for the 16-quart model. Avoid generic "one size fits all" gaskets, as the diameter must be exact to maintain tension.
• Check for Lid Warpage: Place the lid on a completely flat surface (like a granite countertop). If the lid wobbles or doesn't sit flush, the aluminum may have warped due to overheating or a drop. A warped lid cannot be fixed and requires a replacement lid assembly to ensure safety.
• Inspect the Vent Pipe: Ensure the vent pipe (the small tube the weight sits on) is clear of debris. If the pipe is clogged, pressure can build up unevenly and force its way out through the gasket seal rather than the vent. Use a thin wire or pipe cleaner to clear the hole.
• Verify Water Levels: If the pot is overfilled, boiling water can surge upward and "wash over" the seal during the initial heating phase, mimicking a leak. Ensure you are following the specific water-depth requirements for your recipe.

Heads Up

• Gasket Lubrication: Lightly coating the gasket with a tiny amount of vegetable oil can help it seat more effectively and prevent it from sticking or twisting during the locking process.
• Avoid Over-tightening: The Presto 01755 is made of aluminum; applying excessive force to the locking mechanism can strip the threads or warp the rim, leading to permanent leaks.
• Storage Tip: When not in use, store the lid upside down or remove the gasket entirely. Leaving the gasket compressed under a stored lid for months can lead to permanent "flat spots" that cause leaks.
• Safety Warning: If you hear a loud whistling sound coming from the rim rather than the vent pipe, immediately turn off the heat. A failing seal can lead to a dangerous drop in internal temperature, which may result in under-processed food and botulism risks.