How ketchup is made

Flume and wash the tomatoes

A stream of water floats the tomatoes off the trucks, which avoids bruising and gives them a first rinse. After a short wait they tumble through rotating drums for a second wash, and the water drains away.

Sort, chop and pre-cook

A sorting machine picks out fruit of consistent quality. The tomatoes are then reduced and pre-cooked in stainless steel vessels, which preserves them and kills microorganisms.

Pulp out seeds and skins

A cyclone turns the hot fruit into pulp and throws off seeds, skins and stems. The pulp and juice are filtered before moving on. Some plants skip these steps and start from bought-in tomato puree, with a shorter boil.

Boil with the seasoning

The pulp boils in a combined mixing and cooking kettle until it reaches the right concentration. Salt and herbs go in at the start. Sugar may come later to prevent burning, and vinegar arrives at the end with any volatile herbs so their aroma survives.

30 to 45 minutes

Filter and homogenize

A final filtration removes remaining fibers and particles. Some makers then homogenize the sauce, which raises its viscosity.

Pull out the air

Filtering beats air into the sauce, which would feed bacteria, form bubbles and discolor it. A vent removes the air, or the sauce is held at 90 °C for a set time.

Fill hot and cap

The sauce is heated to at least 88 °C so nothing can contaminate it during filling, then goes into glass or plastic bottles. Narrow necks limit its contact with air, and caps go on immediately.

at least 88 °C

Cool the bottles fast

Cold air or cold water brings the filled bottles down straight away, since long storage at high temperature costs flavor. They are labeled and checked, and boxes are often stored upside down to prevent browning in the neck.