Cut a shallow X in the bottom of each tomato. Place the tomatoes in boiling water for 30 to 60 seconds, or until the skins loosen. Transfer immediately to an ice-water bath. Peel, core, and dice the tomatoes. Measure 25 cups after dicing and before blending.
Pulse the tomatoes in a blender or food processor until they reach your preferred consistency. Work in batches and avoid over-blending.
Add the onions, bell peppers, garlic, cilantro, jalapeños, and optional Serrano peppers to a blender with enough tomato juice to help the mixture move. Pulse five or six times, or until coarsely chopped. Work in batches as needed.
Combine the tomatoes, blended vegetables, green chiles, Tabasco sauce, vinegar, sugar, salt, lime juice, and salsa seasoning mix in a large, heavy stockpot. Bring to a simmer.
Simmer uncovered over low heat for 3 to 4 hours, stirring often and scraping the bottom of the pot to prevent scorching.
Ladle hot sauce into hot jars, leaving ½ inch headspace. Remove air bubbles, wipe rims clean, and add lids and rings.
Process quart jars for 40 minutes in a boiling-water canner for altitudes of 1,000 feet or less. Adjust processing time for higher altitudes:1,001 to 3,000 feet: add 5 minutes3,001 to 6,000 feet: add 10 minutes6,001 to 8,000 feet: add 15 minutes8,001 to 10,000 feet: add 20 minutes