Americans putting ketchup on their Fourth of July burgers this week might be surprised to learn that the condiment did not originate in America. Culinary historians have traced its roots to imperial China, where in 300 B.C. “ge-thcup,” “kê-tsiap” or “koe-cheup” was a fermented paste made from fish entrails, meat byproducts and soybeans.

The salty sauce followed trade routes to Indonesia where British sailors discovered it, liked it, and in the early 1700s brought it home. In England, the recipe was amended with the additions, variously, of oysters, mussels, mushrooms, walnuts, white wine, lemons, celery and even fruits like plums, peaches and elderberries. It wasn’t until the early 19th century, though, that tomatoes were added to the condiment, after North Americans finally accepted that they weren’t poisonous. The first known published tomato ketchup (sometimes spelled catsup) recipe appeared in 1812, written by Philadelphia scientist and horticulturalist James Mease. His version called for tomato pulp, spices and brandy but lacked vinegar and sugar.

Today, most Americans eat commercial tomato ketchup. According to the 2018 MRI-Simmons National Consumer Insights Survey, 94.5 percent of us admit to smearing this salty, sweet sauce with its vinegary twang on hot dogs in summer or slathering it over meatloaf in winter; dolloping it on eggs in the morning or dipping fries into it any point in the day. Heinz, America’s first and leading commercial supplier of the stuff, produces over 650 million bottles and 11 billion packets of ketchup annually.

But few Americans realize just how much ketchup we waste. Think about the packets you grabbed the last time you ordered a fast-food burger, never used, and later threw out. Consider the pool of the stuff you left on your plate that last time you polished off a helping of fries. Have you ever looked longingly as that very last bit of ketchup that no matter how hard you try, can’t be coaxed from either the original glass bottle or new-fangled squeezy plastic one before you chuck it in the recycling bin?

Fewer still, understand just how many highly valued tomatoes it takes to fill even a scant quarter-ounce ketchup packet. Well, lucky for you all and your food-waste reduction efforts, I’ve done the math. Using canning queen and cookbook author Marisa McClellan’s recipe, it takes 8 pounds (128 ounces) of ripe Roma tomatoes to produce 48 ounces of her DIY ketchup. Therefore, it takes about 2.7 ounces of tomatoes to make a single ounce of ketchup. As the average plum tomato weighs 2 ounces, it requires a larger-than-average plum tomato to make an ounce of ketchup.

“…making ketchup from scratch is one of the things that everyone should do at least once, if only to appreciate just how many tomatoes it takes to fill a single bottle of Heinz,” McClellan wrote in her third canning book, “Naturally Sweet Food in Jars.”

One most also account for the time (3-4 hours) and fossil fuel energy (the sauce simmers between 1.5 to 2 hours, more if you’re processing the jars to be shelf-stable) required to pull off this DIY condiment project.

Then there is the marketing you’ll have to do to sell your homemade version to your eaters. Before they dip into a jar, they’ll need to understand that – for good or bad – it won’t be an exact replica of the Heinz product they’re probably used to. It will be the right color, yes, but neither as smooth nor glossy nor, most probably, as sweet. Because once you understand just how much sugar it takes to sweeten, even slightly, a simmering pot of acidic tomatoes swimming in vinegar, my guess is you’ll cut back on the sugar or at least swap it for a natural sweetener like maple syrup, as McClellan does. But your homemade ketchup will be your own, and as you learn to tailor the final taste to your own, it will become more and more delicious.

Once you’ve tackled ketchup, we can talk about making mustard and relish, as well. The former is simpler to pull off than ketchup, the latter a bit more involved. But making all your summer picnic condiments will both honor their individual ingredients in the short term and cut down on single-use plastic packaging in the long.

Christine Burns Rudalevige is a food writer, recipe developer, tester and cooking teacher in Brunswick, and the author of “Green Plate Special,” a cookbook from Islandport based on these columns. She can be contacted at:

[email protected]

Looking for a kitchen project this July 4 holiday? Try making your own ketchup. It takes umpteen tomatoes to make even a single bottle. Ben McCanna/Staff Photographer

DIY Maple-Sweetened Tomato Ketchup

This recipe is adapted from one developed by canning expert Marisa McClellan. She uses fresh tomatoes and red bell pepper, but I’ve used canned and roasted ones, respectively. It’ll be late summer before fresh tomatoes and bell peppers will be in Maine in great enough quantity to make using them for canning affordable. You’ll need 5-6 clean, eight-ounce jars for this recipe.

Makes 5-6 (8-ounce) jars

2 large (28-ounce) cans peeled, whole Roma tomatoes

1 medium yellow onion, diced

1 cup chopped roasted red pepper

2 cups apple cider vinegar

1 cup maple syrup

1/4 cup bottled lemon juice

1 tablespoon kosher salt

1 teaspoon celery seeds

1/2 teaspoon Aleppo pepper flakes or 1/4 teaspoon cayenne pepper

1 teaspoon whole cloves

1 teaspoon yellow mustard seeds

1 teaspoon whole allspice berries

1 cinnamon stick, crushed

Combine the tomatoes, onion and bell peppers in a large, non-reactive pot. Bring to a boil and cook until the vegetables are entirely soft, about 30 minutes.

Position a sieve or food mill over a large bowl and work the tomato mash through the mechanism. Once the tomato pulp has been separated from the seeds and skins, return the pulp to the pot. Compost the seeds and skins.

Add the vinegar, maple syrup, lemon juice, salt, celery seeds and Aleppo or cayenne directly to the pot. Using a spice bag, tea ball or length of cheesecloth, bundle up the cloves, mustard seed, allspice and cinnamon and place the bundle into the pot.

Simmer the mixture over medium-low heat, stirring regularly, until it has reduced by half and reached the desired thickness, 1 to 2 hours. Ladle the ketchup into the clean jars. They will store well in the refrigerator for 3 weeks or you can process them in a boiling water bath for 10 minutes to make them shelf stable.