Wash tomatoes
Remove stems and blemishes
Blanch tomatoes in boiling water for 30 to 60 seconds
Transfer tomatoes to ice water
Peel skins off
Remove cores
Chop tomatoes
Cook tomatoes in a large pot until softened
Blend or mash to desired consistency
Simmer sauce until thickened
Add bottled lemon juice or citric acid to each jar for safe acidity
Sterilize canning jars, lids, and bands
Fill hot jars with hot sauce, leaving proper headspace
Remove air bubbles
Wipe jar rims clean
Place lids on jars and screw bands fingertip-tight
Process jars in a boiling water bath for the recommended time based on jar size and altitude
Remove jars and let them cool undisturbed for 12 to 24 hours
Check that lids have sealed
Label jars
Store sealed jars in a cool, dark place