Now the steam canner has been filled, and brought up to operating temperature. See the cloud of steam escaping just below the yellow warning sticker? There is a second tiny hole in the opposite side of the cover. Follow all the directions which are clearly written in the booklet which comes with the steam canner. It is for use only on foods safe for water bath canners. It is NOT a Pressure Canner. Only 6-8 cups of water are boiled in the water pan, so it comes up to working temperature in far less time, and uses far less fuel than a water bath canner. I did three batches of 7 pints of zucchini relish, and did not need to top off the water pan.