What Is a Plum Tomato: Definition and Culinary Uses

Plum tomatoes are oval-shaped, meaty tomatoes with fewer seeds and less water content than round varieties, making them ideal for sauces, canning, and cooking where a thick, rich tomato flavor is essential. Discover why professional chefs prefer them for pasta sauces, their key characteristics, and how to use them effectively in your kitchen.

What Exactly Defines a Plum Tomato?

Plum tomatoes, also known as paste tomatoes or processing tomatoes, belong to the Solanum lycopersicum species but feature distinct characteristics that set them apart from common slicing varieties. These tomatoes have an elongated, egg-like shape with a firm, dense flesh and significantly fewer seed cavities. According to the USDA Agricultural Research Service, plum tomatoes typically contain 10-20% less water than standard round tomatoes, which directly contributes to their concentrated flavor profile.

The reduced moisture content isn't their only advantage. Plum tomatoes boast higher solid content, including more flesh and less juice, which translates to better texture retention during cooking. This structural difference makes them the preferred choice for culinary applications requiring thick sauces without lengthy reduction times.

Key Characteristics That Make Plum Tomatoes Special

Understanding what makes plum tomatoes unique helps explain their culinary value:

• Shape and size: Typically 3-4 inches long with an oval or cylindrical shape
• Internal structure: Fewer seed compartments (locules) than round varieties
• Skin thickness: Thicker skin that holds up better during processing
• Flavor concentration: Higher ratio of solids to liquid creates richer taste
• Acidity level: Balanced acidity that enhances preservation and flavor development

Characteristic	Plum Tomatoes	Round Slicing Tomatoes
Water content	75-80%	90-95%
Seed cavities	2-3	4-6
Solids content	8-12%	4-6%
Best culinary use	Sauces, paste, canning	Fresh eating, salads

Why Chefs Choose Plum Tomatoes for Serious Cooking

Professional kitchens consistently reach for plum tomatoes when preparing sauces, and for good reason. The University of California Davis Department of Plant Sciences confirms that the lower water content in plum varieties like Roma and San Marzano reduces cooking time by up to 40% when making tomato sauce compared to standard varieties.

When you're making a classic marinara or arrabbiata, using plum tomatoes means:

• You'll spend less time reducing liquids to achieve the perfect consistency
• The sauce develops deeper flavor more quickly
• Less chance of "watering down" your finished dish
• Better texture retention during long cooking processes

Common Plum Tomato Varieties You Should Know

Not all plum tomatoes are created equal. Different varieties offer unique flavor profiles and textures:

• Roma: The most widely available commercial variety, known for reliable performance in sauces
• San Marzano: DOP-protected Italian variety with sweeter flavor and fewer seeds (officially recognized by the Italian government as superior for sauces)
• Amish Paste: Heirloom variety with complex flavor and meaty texture
• Opalka: Large plum variety with exceptionally sweet flavor
• Viva Italia: Disease-resistant hybrid popular with home gardeners

The Consorzio del Pomodoro San Marzano dell'Agro Sarnese-Nocerino maintains strict standards for authentic San Marzano tomatoes, requiring specific growing conditions in a designated region of Italy to earn the DOP certification. This explains why genuine San Marzano tomatoes often command premium prices.

How to Select and Store Plum Tomatoes

Choosing quality plum tomatoes makes a significant difference in your cooking results. Look for these indicators of freshness and quality:

• Firmness: Should feel dense and heavy for their size
• Color: Deep, uniform red without green shoulders (except for heirloom varieties)
• Skin: Smooth and taut without wrinkles or blemishes
• Stem: Should be firmly attached with green, fresh-looking cap

For optimal flavor development, store unripe plum tomatoes stem-side down at room temperature away from direct sunlight. Once fully ripe, use within 2-3 days or refrigerate for up to 5 days (though refrigeration can affect texture). The USDA recommends against storing tomatoes below 50°F (10°C) as it damages flavor compounds.

Culinary Applications Beyond Basic Sauce

While plum tomatoes shine in sauces, their versatility extends to numerous cooking applications:

• Concentrated tomato paste: Their low moisture content creates richer paste with less processing
• Dried tomatoes: Require less drying time and develop more intense flavor
• Canned whole tomatoes: Maintain shape better during processing
• Tomato soup: Creates naturally thicker base without additional thickeners
• Stuffed tomatoes: Firm flesh holds shape when hollowed and filled

When substituting plum tomatoes in recipes calling for other varieties, remember to adjust liquid content. For every pound of plum tomatoes replacing round tomatoes, reduce additional liquids by approximately 25% to maintain proper consistency.

Growing Plum Tomatoes: What Home Gardeners Should Know

If you're considering growing your own plum tomatoes, Cornell University's College of Agriculture and Life Sciences notes these varieties typically:

• Require 70-80 days to reach maturity from transplant
• Produce determinate growth (bush-type) plants that stop growing at a certain height
• Yield concentrated harvests ideal for canning batches
• Generally show better disease resistance than many heirloom varieties

For best results, provide consistent moisture (1-2 inches per week), full sun exposure, and support structures as the fruit develops. The determinate growth habit means these plants won't continue producing throughout the season like indeterminate varieties, but they deliver a substantial harvest within a shorter timeframe.

Common Substitutions When Plum Tomatoes Aren't Available

Ran out of plum tomatoes but need to make sauce tonight? Consider these alternatives with appropriate adjustments:

• Cherry tomatoes: Surprisingly good substitute but requires longer reduction time (use 25% more)
• Vine-ripened tomatoes: Better than standard round tomatoes but still needs extended cooking
• Canned whole tomatoes: Drain excess liquid before use to mimic plum tomato consistency
• Tomato paste + water: For emergency situations, mix 1 part paste with 2 parts water

Remember that while substitutions work in a pinch, they won't deliver the same texture and flavor concentration as genuine plum tomatoes. The National Center for Home Food Preservation recommends against using standard slicing tomatoes for canning due to their lower acidity levels compared to plum varieties.

Frequently Asked Questions About Plum Tomatoes

Why are plum tomatoes better for sauce than regular tomatoes?

Plum tomatoes contain less water and more flesh than regular tomatoes, resulting in a thicker, richer sauce with less cooking time. Their lower moisture content (75-80% versus 90-95% in round tomatoes) means sauces made with plum tomatoes require up to 40% less reduction time to reach proper consistency.

Can I use regular tomatoes instead of plum tomatoes for canning?

While possible, it's not recommended. Plum tomatoes have higher natural acidity and lower water content, which are critical for safe canning. The National Center for Home Food Preservation advises against using standard slicing tomatoes for canning due to potential safety issues from lower acidity levels.

What's the difference between San Marzano and Roma tomatoes?

San Marzano tomatoes are a specific DOP-protected Italian plum tomato variety with a sweeter flavor, fewer seeds, and thicker flesh than standard Roma tomatoes. Authentic San Marzano tomatoes must be grown in a designated region of Italy and meet strict quality standards maintained by the Consorzio del Pomodoro San Marzano.

How should I store fresh plum tomatoes?

Store unripe plum tomatoes stem-side down at room temperature away from direct sunlight. Once fully ripe, use within 2-3 days or refrigerate for up to 5 days. The USDA recommends against storing tomatoes below 50°F (10°C) as it damages flavor compounds, so keep refrigeration as a last resort for ripe tomatoes you can't use immediately.

Are plum tomatoes determinate or indeterminate plants?

Most commercial plum tomato varieties are determinate (bush-type) plants that grow to a certain height and produce a concentrated harvest. This makes them ideal for canning batches. However, some heirloom plum varieties may be indeterminate, continuing to grow and produce fruit throughout the season.