The Ultimate Homemade Ketchup (Lacto Fermented)
The Ultimate Homemade Ketchup (Lacto Fermented) is a medium American recipe that serves 8. 20 calories per serving. Recipe by Joshua Weissman on YouTube.
Prep: 20 min | Cook: 72 hrs 5 min | Total: 72 hrs 40 min
Cost: $5.10 total, $0.64 per serving
Ingredients
- 340 grams Tomato Paste (Two 6‑ounce cans, blended until smooth)
- 73 milliliters Water (Room temperature)
- 42 grams Granulated Sugar (White granulated sugar)
- 5 grams Kosher Salt (Fine kosher salt)
- 45 milliliters Whey (or brine from lacto‑fermented veg) (Liquid from a lacto‑fermented vegetable jar; provides starter cultures)
- 60 milliliters Apple Cider Vinegar (Raw, unfiltered)
- 236 milliliters Mayonnaise (Homemade or store‑bought, optional for burger sauce)
- 30 milliliters Pickles (finely diced) (Optional garnish for sauce)
- 15 grams Black Garlic (Finely chopped, optional flavor boost for sauce)
Instructions
Make sugar‑water syrup
Combine 73 ml water and 42 g granulated sugar in a small saucepan. Heat over medium heat, stirring occasionally, until the sugar is fully dissolved. Remove from heat before the mixture reaches a boil.
Time: PT5M
Combine tomato paste and seasonings
In a medium mixing bowl add the 340 g tomato paste, 5 g kosher salt, the warm sugar‑water syrup, 45 ml whey (or brine), and 60 ml raw apple cider vinegar. Mix thoroughly until the mixture is completely smooth.
Time: PT5M
Pack mixture into mason jar
Using a funnel, spoon the ketchup mixture into a clean 1‑pint mason jar, leaving about 1‑2 cm headspace. Secure the jar with the two‑piece lid and attach the airlock.
Time: PT2M
Ferment at room temperature
Place the sealed jar in a room‑temperature spot (68‑72 °F / 20‑22 °C) out of direct sunlight. Let it ferment for 2‑4 days, checking daily for tiny bubbles in the airlock. The ketchup will develop a deeper, more acidic flavor.
Time: PT72H
Temperature: 68‑72°F
Finish and store
After fermentation, optionally pass the ketchup through a fine mesh sieve or chinois for a smoother texture. Transfer to a clean container and refrigerate.
Time: PT5M
Prepare fermented ketchup burger sauce (optional)
In a bowl combine 236 ml mayonnaise with 118 ml of the fermented ketchup. Season generously with salt and stir in optional finely diced pickles and chopped black garlic. Mix until fully incorporated.
Time: PT5M
Nutrition Facts
- Calories
- 20
- Protein
- 0g
- Carbohydrates
- 5g
- Fat
- 0g
- Fiber
- 0g
Dietary info: Vegetarian, Gluten-Free
Allergens: Tomato, Dairy (whey), Egg (if mayonnaise added)
Ingredient Substitutions
- Instead of Tomato Paste: Tomato puree, Crushed tomatoes (drained)
- Instead of Granulated Sugar: Honey, Maple syrup (use less)
- Instead of Kosher Salt: Sea salt
- Instead of Whey (or brine from lacto‑fermented veg): Kombucha starter, Sauerkraut brine
- Instead of Apple Cider Vinegar: White wine vinegar, Rice vinegar
- Instead of Mayonnaise: Aioli, Vegan mayo
- Instead of Pickles (finely diced): Capers
- Instead of Black Garlic: Roasted garlic
Equipment Needed
- Small Saucepan
- Measuring Spoons
- Medium Mixing Bowl
- 1‑Pint Mason Jar with Airlock Lid
- Funnel (optional)
- Fine Mesh Sieve or Chinois (optional)
- Spatula or Spoon
Critical Steps — Do Not Skip
- Heat sugar‑water syrup without boiling
- Mix tomato paste until completely smooth
- Use a glass jar (no metal) for fermentation
- Seal with an airlock to avoid frequent burping
- Ferment for 2‑4 days at consistent room temperature
- Optional straining for a silky finish
Chef Tips from the Video
- Use high‑quality tomato paste with no added sugars for the cleanest flavor.
- Raw, unfiltered apple cider vinegar adds depth and keeps the fermentation lively.
- Whey from homemade sauerkraut gives the most robust probiotic boost.
- Label the jar with the start date to track fermentation progress.
- Store the finished ketchup in a dark corner of the fridge to preserve color.
Troubleshooting
No bubbles appear during fermentation.
Make sure the whey you used contains active cultures and keep the jar in a warm spot (around 70 °F). You can also add a pinch of raw honey to jump‑start fermentation.
Ketchup is too thin after fermentation.
Blend the mixture longer, or pass it through a fine mesh sieve and stir in a little extra tomato paste to thicken.
Off‑smelling or moldy surface.
Discard the batch immediately; contamination can occur if the jar wasn’t sealed properly or if the temperature was too high.
Storage
Refrigerator: Up to 2 weeks
Freezer: Up to 3 months (freeze in airtight container)
Room temperature: Not recommended after fermentation; keep at room temperature only during the 2‑4 day ferment
Make-Ahead Tips
- The fermented ketchup can be made up to two weeks in advance and stored in the refrigerator.
- If you want a more intense flavor, let it ferment up to 7 days, checking for off‑odors.
- Freeze portions in ice‑cube trays for easy single‑serving use.
Frequently Asked Questions
What is the cultural significance and history of ketchup in American cuisine?
Ketchup originated as a fermented fish sauce in 17th‑century China and Southeast Asia, later evolving in the United States into a sweet tomato‑based condiment in the 19th century. It became a staple of American fast food and home cooking, symbolizing convenience and comfort.
How does lacto‑fermented ketchup differ from traditional store‑bought ketchup in terms of flavor and nutrition?
Lacto‑fermented ketchup develops deeper umami, tangy acidity, and a slight probiotic boost from the live cultures, whereas store‑bought ketchup relies on added sugars and preservatives for flavor. The fermented version also contains fewer added sugars and no artificial additives.
What traditional regional variations of ketchup exist within American cuisine?
In the Southern United States, ketchup is often spiced with hot sauce or mustard; in the Midwest, a sweeter, tomato‑heavy style is common. Some regional recipes add fruit purées like apple or mango for a unique twist, similar to the fermented version’s fruit‑based acidity.
What occasions or celebrations is ketchup traditionally associated with in American culture?
Ketchup is a ubiquitous side for casual gatherings such as barbecues, picnics, and fast‑food meals. It’s also a staple at family game nights, sports viewing parties, and holiday buffets where fries, burgers, and hot dogs are served.
What other American dishes pair well with lacto‑fermented ketchup?
Lacto‑fermented ketchup shines with classic American foods like cheeseburgers, chicken tenders, sweet potato fries, and as a glaze for meatloaf. It also works as a base for BBQ sauces or mixed into deviled eggs for a tangy twist.
What are the authentic traditional ingredients for ketchup versus acceptable substitutes?
Traditional American ketchup uses tomato concentrate, distilled vinegar, sugar, salt, and spices. Acceptable substitutes include tomato paste (as used in this recipe), raw apple cider vinegar for a brighter acidity, and whey or brine as a starter culture for fermentation.
What are the most common mistakes to avoid when making lacto‑fermented ketchup?
Common errors include boiling the sugar‑water syrup (which can caramelize), using metal containers that react with acid, skipping the whey starter, and fermenting at temperatures below 60 °F, which stalls the culture. Also, forgetting to label the jar can lead to confusion later.
Why does this lacto‑fermented ketchup recipe use whey instead of a commercial starter culture?
Whey provides a natural source of lactobacillus bacteria already adapted to acidic environments, making it an inexpensive, readily available starter. Commercial cultures work too, but whey adds a subtle dairy‑derived flavor that complements the tomato base.
Can I make lacto‑fermented ketchup ahead of time and how should I store it?
Yes, you can ferment the ketchup up to a week before you need it. After fermentation, refrigerate the sealed jar; it will keep for about two weeks. For longer storage, freeze in airtight containers for up to three months.
What does the YouTube channel Joshua Weissman specialize in?
The YouTube channel Joshua Weissman focuses on detailed, technique‑driven home cooking tutorials, often recreating classic dishes from scratch, emphasizing flavor, precision, and a playful personality.
How does the YouTube channel Joshua Weissman's approach to American comfort food differ from other cooking channels?
Joshua Weissman blends rigorous culinary fundamentals with a casual, humorous style, often adding unique twists like fermentation or homemade condiments. Unlike many channels that rely on shortcuts, he encourages making foundational components—like ketchup—from scratch for superior taste.
Last updated: August 10, 2026
