How Long to Cold Pack Tomatoes | A Complete Processing Guide

Cold packed tomatoes in a boiling water bath require 85 minutes for both pints and quarts at altitudes up to 1,000 feet.

You just spent a hot August afternoon hauling a bushel of Romas from the garden. The jars are washed, the lids are simmering, and the plan is to get dinner started before you put the tomatoes away. Then you glance at the processing chart and see the number 85 — 85 minutes. That is not a typo.

Cold packing — filling jars with raw tomatoes and covering them with liquid — is one of the simplest ways to preserve the harvest. The tradeoff is an unusually long time in the boiling water bath. Exactly how long depends on the liquid you add and the canner you use. This guide breaks down the exact times for every standard method.

What Exactly Is Cold Packing Tomatoes?

Cold packing, formally called raw packing, means you skip the pre-cooking step. Raw tomatoes get blanched, peeled, cored, and packed tightly into jars. You cover them with boiling water or hot juice, then the jar goes straight into the canner.

This contrasts with hot packing, where you simmer the tomatoes for about 5 minutes before loading the jars. Each method has a purpose. Hot-packed jars hold more volume because the fruit softens and settles. Cold-packed jars tend to keep the fruit firmer and more intact.

Either way, leave a half-inch of headspace. Wipe the rims clean, adjust the lids, and get ready for a longer-than-average bath time.

Why the 85-Minute Time Surprises Most People

If you have canned green beans or peaches before, you are used to 20 or 30 minutes in the canner. Seeing 85 minutes feels like a misprint. The reason comes down to heat transfer and food safety.

• Cold fruit, long come-up time: Raw tomatoes start cold inside the jar. The canner must heat the fruit, the liquid, and the glass evenly from the outside in. That takes much longer than simply reheating already-hot fruit.
• Density slows heat penetration: Whole tomatoes are dense. Heat moves through a jar packed tight with Roma tomatoes significantly slower than it moves through a jar of loosely packed green beans or cucumber pickles.
• Tomato acidity is borderline: Ripe tomatoes sit right at the edge of the acidity level needed to inhibit botulism spores. The long processing time is not just for cooking — it is a critical safety margin.
• Hot packing saves time: If you do not want to wait 85 minutes, hot packing cuts the boiling water bath time to roughly 40 minutes for pints and 45 for quarts. You trade some texture for speed.

Knowing why the time is so long makes it easier to plan your canning day. Set a timer, start a podcast, and let the canner do its work.

Cold Pack Processing Times by Method and Liquid

The exact processing time depends on two variables: the liquid you add and the type of canner you use. Water-packed jars require the longest times. Juice-packed jars process faster because the liquid is less dense and conducts heat more aggressively.

The National Center for Home Food Preservation publishes the authoritative numbers using their specific raw pack processing time table. The standard times for a boiling-water canner at altitudes up to 1,000 feet are straightforward.

Notice that water-packed quarts and pints both clock in at 85 minutes. The density of the fruit itself is the bottleneck, not the jar size. Juice-packed jars heat faster because the liquid transfers heat more efficiently than plain water.

How to Cold Pack Tomatoes Step by Step

Getting those 85 minutes to result in safe, shelf-stable jars depends entirely on the prep work. The steps before the canner matter just as much as the timer.

1. Blanch and peel: Score a small X on the bottom of each tomato. Lower them into boiling water for 30 to 60 seconds, then transfer to an ice bath. The skins slip right off.
2. Core and trim: Cut out the stem core and any green or bruised sections. Green areas are less acidic and can affect the safety of the entire batch.
3. Pack firmly: Place tomatoes into the jar, pressing gently until the spaces between them fill with their own juice. Pack to within half an inch of the rim.
4. Add liquid: Pour boiling water or hot tomato juice over the packed fruit, maintaining that half-inch headspace.
5. Process by canner type: For a pressure canner, the time drops to 25 minutes for water-pack. For a steam canner, follow the same times as the water bath but start the clock only once the steam column is venting steadily.

Let the jars cool undisturbed for 12 to 24 hours. Check the seals, label them, and store in a cool, dark place away from direct light.

Altitude Adjustments and the Botulism Question

If you live above 1,000 feet, the standard times do not apply. Water boils at a lower temperature at higher altitudes, so the inside of the jar cannot reach a safe processing temperature without extending the time.

As the tomato acidity botulism risk guide explains, ripe tomatoes sit right on the edge of the acidity borderline. This creates confusion for home canners, which is why following a tested recipe is non-negotiable. The adjustments for a boiling-water canner are simple.

Pressure canning adjusts pressure rather than time. At 11 PSI (dial gauge) or 10 PSI (weighted gauge), the standard times hold up to 2,000 feet. Above that, consult a full altitude adjustment chart from your local extension office.

The Bottom Line

Cold packing tomatoes means committing to 85 minutes in the boiling water bath for water-packed jars. It is one of the longest processing times in home canning, but it preserves the firm texture of fresh tomatoes better than hot packing. For juice-packed jars, the time drops to a more manageable 35 or 45 minutes.

Before loading up your canner, take the time to check your specific altitude against the NCHFP adjustment tables — your local county extension office can help confirm the numbers and keep your canned tomatoes safe through the winter.