Before I save tomato seeds I cut a tomato and taste it first. I want to make sure I have a good tasting tomato before I save seeds from it.
I push the seeds out of the tomato into a 5 gallon bucket of water. I save seeds from several good tasting tomatoes. I don't save seeds from deformed tomatoes or plants that have problems.
Seeds have enzymes on them that keep seeds from germinating inside the wet tomato. I let seeds soak in a 5 gallon bucket of water until the next day or maybe 2 or 3 days this removes the enzymes so seeds germinate very easy. I scoop the seeds out of the water with a 6" diameter screen wire strainer. I push the seeds around the screen wire with my finger most of the gel stuff pushes through the screen wire or sticks to the wire.
I dump the seeds on a paper plate to dry in the kitchen. Usually before bed time the paper plate has soaked up most of the water so I scrap the seeds onto another dry paper plate.
Next morning seeds are looking much dryer but they need to dry for several days before putting them into enveloped with labels and dates.
I took 12 seeds from the tomato seed pack and planted them in plant trays and they all grew. I set the trays under a shade tree when plants were 6" tall I planted them in the garden. Now the tomato plants are knee high and doing fine. It looks like I have a good pack of tomato seeds. I hope to have tomatoes I can taste by November I want to make sure these seeds are worth saving and growing next spring. We love the flavor of all the Beef Steak varieties, Big Beef, Beef Master & Jet Star. I planted all Big Beef tomatoes this year.