Empty means no jars of anything, not even jars of water? Then the empty volume inside is much larger than normal. With nothing in it except the 3" of water it will take it a really long time to build up enough steam volume to displace all that air and develop a steady stream of steam.

30 min sounds like a long time but if you started with just tap water then depending on your stove it could take 30 min.

But the "flapping noise sounds like the gasket isn't in right and isn't sealing. If that is the case air is sucked in from outside around the rim and you'll never get a full head of steam.

Try removing, inspecting carefully and reseating the gasket (how long since it was replaced?) and then give it a run with 2-3 jars filled with water in it to decrease the empty volume. Oil the gasket if necessary.

Dave

Thanks, Dave. I'll try that and run again with jars of water.

Did you look in the vent pipe and clean it out ? Try flossing it with some kitchen twine or something.

In that canner the lid lock usually will come up when it starts venting properly, when there is a heavy stream of steam. Is the lid lock coming up ?

I checked the vent pipe first, since that seemed to be the most obvious place to cause this kind of problem. It was clear. No problems. I didn't see any bubbling or leakage anywhere. Tried oiling the gasket; it was only a year old and not used too often. Still had same problem. Filled 4 jars with water this time. The lid lock comes up shortly after I begin to see the steam. This time the flapping sound didn't start until the steam was going pretty strong, but there is still stopping and starting of the "funnel" and the flapping sound. DH just went out to get new gasket for me. I'll try again to see if that makes a difference.

A year old gasket shouldn't need replacing for any reason even if the canner was stored with the lid locked down on it. Not unless it has gotten torn or broken somehow.

You can always heat the gasket in hot water to re-expand it. Plus make sure it is in right side up - that seems to be a common problem - upside downs gaskets.

Did you check the pop-off valve and make sure it hasn't popped up part way for some reason?

Have you used the canner on this stove successfully in the past? Is it a glass top stove with cycling burners?

Personally if it is steaming well even if it appears to be intermittent, I'd put the weight on it and see what happens with the pressure. The seeing intermittent steam vs. continuous steam has a lot of personal perception issues depending on light, the background, etc.

Dave

Dave, I've used this pressure canner for 6 years now with no problems. I used it earlier this season with no problem. Stored the lid off the canner. The pop-up comes up after what sounds like a full boil. I have a gas stove. It's on the largest burner, and I had it set on High. I guess it's the combination of sporadic funnel with that strange clacking sound that I never heard before that has me concerned. I did put on the weights and it did come up to 10 with no problems, and the gauge read 12 (which is what the extension office had told me). Do you think it's okay? Just concerned cause I have been reading about pockets of air causing the un-steady stream of steam and I never saw this before. For now I'm just BWB my tomatoes to get them done. But I do want to do some green beans soon, so I hope to figure this out.

Personally yeah, if it is steaming well for several mins and then you do the 10 min vent then I think it is fine. Even if the steam cone hiccups a bit. Even condensation in the vent tube can make it do that.

I can't explain the flapping sound though other than to see if it goes away as pressure rises.

Dave

PS: check the over-pressure plug too. it may need a new gasket.

Thanks again, Dave. I'm feeling pretty secure and will try again after I finish with all these tomatoes. Can't believe how many we're still getting this late in the season. We usually have frost by this date. They started late because of an early heat wave but are sure making up for it now. Going to replace the pop-up valve and gasket just to be sure. Which way does it go? Concave against lid or the reverse?

Well, replaced gasket, pop-up and tightened everything. Don't know which fixed it, but canner venting fine now and flapping sound is gone. Working like a well-oiled machine. Thanks again, Dave. Now on to the green beans. My grandmother used to make wonderful sweet and sour green beans that I would love to replicate. Anyone know of a recipe like that?