Cheese Profile

What Is Leerdammer Cheese and Why Does It Have Holes?

Leerdammer is a Dutch cow's milk cheese designed to join Gouda mildness with Emmental-style holes. Learn its taste, label, melting, serving, and storage.

Leerdammer wheel and wedge with large round holes - Leerdammer | KnowTheCheese
LEERDAMMER QUICK FACTS
OriginLeerdam, Netherlands
MilkPasteurized cow's milk
TextureSupple and semi-firm with large eyes
RindTreated outer coating, not part of the paste
AgingVaries by product
FlavorMild and nutty
AvailabilitySupermarkets and European cheese counters

Leerdammer is a branded Dutch cow's milk cheese created to combine the mild taste associated with Gouda and the large holes associated with Emmental. The result is supple, mildly nutty, and easier to fold or melt than a dry aged cheese.

Cees Boterkooper and Baastian Baars developed it in 1974, and the name comes from Leerdam, where Boterkooper's dairy stood. It is a modern product with a documented design, not a centuries-old protected regional style.

Why Was Leerdammer Designed Between Two Cheeses?

The founders wanted a Dutch cheese that kept Gouda's gentle flavor while carrying the conspicuous openings of Emmental. That goal still explains the product more clearly than calling it simply “Swiss cheese” or “Gouda with holes.”

Leerdammer Original uses pasteurized milk, salt, starter culture, and vegetarian rennet. The short list leaves fermentation, moisture, and maturation to create most of the aroma and structure.

The distinction is useful at the counter. Leerdammer is a brand with a documented recipe and history, while “Swiss cheese” is often a broad retail label that does not promise the same flavor, hole pattern, rind treatment, or vegetarian status.

The official process also narrows what the name means.

Pasteurized milk is curdled with a microbial enzyme, cultured, moulded, pressed, held in brine for more than two days, matured under observation, and finally coated to preserve the supple body.

Each stage supports the intended middle position. Pressing gives the curd enough continuity to hold expanding gas, while brining seasons the wheel and firms its surface before the cultures continue their work during maturation.

The protective coating comes last because the interior structure must develop first. It helps the finished wheel retain moisture, but it does not create the holes or the nutty flavor that distinguish the cheese.

Why Does Leerdammer Have Large Holes?

The holes are intentional spaces formed as ripening cultures produce gas inside an elastic curd.

Pressure collects at weak points and expands rounded pockets instead of escaping through a dry open surface.

Round gas-formed holes across a Leerdammer cut face - Leerdammer | KnowTheCheese
Rounded eyes show where gas expanded inside a paste flexible enough to hold it.

Hole size varies across a wedge because gas does not collect in a perfect grid. Rounded eyes with clean interiors fit the style, while wet fissures, crumbling around the openings, or an inflated package require a separate freshness check.

The brand says one house ferment develops the holes and delicate nuttiness, while another can strengthen flavor as maturation continues. That connects the visible eyes and the taste to controlled fermentation rather than to holes being punched into the cheese after it is made.

Leerdammer says the hole-forming ferment has remained unchanged since the brand's early years.

The continuity matters because the eyes and mild nutty flavor come from the same controlled make, rather than being two unrelated product features.

The curd must remain elastic while the gas accumulates. If it were too dry or brittle, pressure would be more likely to form splits instead of the smooth rounded openings visible in a normal slice.

That relationship also explains why the paste immediately around a hole should feel like the rest of the cheese. A clean eye is empty space within a continuous body, not a wet cavity or a weak ring of crumbling curd.

How Is It Different from Gouda and Emmental?

Young Gouda usually presents a close, springy paste and a milky sweetness. Emmental brings larger eyes and a more recognizably Alpine nutty profile.

Gouda Leerdammer and Emmental textures compared side by side - Leerdammer | KnowTheCheese
Leerdammer occupies a visual and sensory middle ground rather than copying either comparison exactly.

Leerdammer keeps the flavor deliberately mild and the body pliable while making the eyes part of its identity. Choose it when you want obvious nuttiness and a holed slice without the firmer chew or stronger finish of some Alpine wheels.

The comparison also sets expectations in cooking.

A young Gouda-like moisture level helps a thin slice soften promptly, while the elastic body around the eyes keeps it from behaving like a loose fresh cheese.

The comparison is about the result, not a recipe made by mixing two finished cheeses. Leerdammer begins as one batch of milk and develops its own balance through cultures, pressing, brining, maturation, and coating.

What Does Leerdammer Original Taste Like?

The first impression is creamy and restrained, followed by a rounded nutty note as the paste warms. Its salt is present but does not dominate the finish.

The texture yields rather than crumbles, which spreads the flavor across the palate and supports the brand's “melt-in-your-mouth” description. Very cold slices feel firmer and reveal less aroma, so a short rest improves a board serving.

Look for a clean dairy aroma and a finish that stays gently nutty.

Sharp ammonia, fermented sweetness from a swollen pack, or moisture collecting in broken holes belongs to a condition check, not to the intended flavor profile.

Cut shape changes the sequence of that flavor. A thin folded slice warms quickly and emphasizes creaminess, while a thicker piece gives the elastic chew enough time for the nutty note to become more obvious.

For a board, cut across several eyes instead of trimming around them. The openings are part of the intended texture, and the surrounding paste provides the flavor and resistance that make each piece complete.

Can You Melt Leerdammer?

A current 100-gram serving reference lists 27.5 grams of fat and 27 grams of protein. That balanced cheese matrix softens readily, but the practical control is slice thickness rather than the nutrition panel.

Leerdammer melting inside a rye bread toastie - Leerdammer | KnowTheCheese
Thin folded slices warm through quickly and fill the spaces created by the eyes.

Fold thin slices in a toastie, omelet, or hot sandwich so the layers trap heat. A thick cold slab can leave a rubbery center while its outer surface releases fat.

The same thickness rule helps in an omelet.

Tear or fold a slice across the hot center just before the egg sets, then close it so residual heat softens the cheese without keeping the pan over high heat.

In a toastie, overlap two thin slices rather than using one thick block. The bread then receives cheese across the whole surface, and the center reaches a soft cohesive state before the crust burns.

What Does “Lactose Free” Mean on This Label?

Leerdammer Original states that it contains less than 0.01 percent lactose. That is a measured product claim, not a statement that the cheese is milk-free.

NOTE

Lactose intolerance and milk allergy are different. Leerdammer still contains cow's milk proteins and is unsafe for someone with a milk allergy even when the lactose level is below the stated threshold.

Check the exact pack because branded ranges can contain several formats and recipes. People managing a medical condition should follow their clinician's advice instead of applying the Original label to every Leerdammer product.

Can You Eat the Rind?

The Dutch ingredient list states that natamycin is used in the rind. It controls unwanted surface growth on the exterior and should not be confused with an edible natural rind developed for flavor.

Thin treated coating along the edge of a Leerdammer wedge - Leerdammer | KnowTheCheese
Trim the treated outer edge while preserving the pale cheese immediately beneath it.

If a cut wedge includes a visibly distinct coating, trim that edge before serving or melting. Do not remove a thick band of good paste merely because the outermost millimeter has a different color or feel.

Whole wheels receive a protective coating after maturation to help retain their supple texture. On a retail wedge, follow the visible boundary between coating and paste instead of treating every dry-looking outer edge as an edible flavor rind.

Is Leerdammer Vegetarian?

The producer lists vegetarian rennet and describes Original as suitable for vegetarians. It also lists pasteurized milk and 850 milligrams of calcium per 100 grams, which is 106 percent of the reference intake used on that market label.

Those facts apply to the current Original product page. Read imported packs directly because formulations, serving references, and labeling language can differ by market.

Do not transfer the claim automatically to every product carrying the brand.

Original slices, blocks, flavored versions, and market-specific packs can present different ingredient or nutrition panels, so the exact pack remains the owner of the dietary answer.

How Should You Buy and Store It?

Pre-sliced Leerdammer is convenient for sandwiches but exposes more surface to air.

A wedge retains moisture longer and lets you control slice thickness for boards or cooking.

Whichever format you choose, look for pale supple paste, clean rounded eyes, and a package that lies flat rather than ballooning. A little moisture on a newly opened slice can come from temperature change, but persistent liquid inside several holes is a reason to inspect the date and aroma closely.

BUYING TIPS
Inspect the eyes
Clean rounded openings are normal; wet cracks and swollen packaging are not.
Check the edge
Plan to trim any visibly treated outer coating.
Match the format
Buy slices for immediate sandwiches and a wedge for flexible cutting.
Read the exact pack
Confirm lactose, rennet and use-by information on the product in your market.

Keep the pack refrigerated and press wrap against newly exposed paste. Separate slices with their original interleaving paper, and warm only what you will serve so the rest does not repeatedly sweat and cool.

Store a wedge with the treated outer edge intact until you need that portion because the coating slows moisture loss. Once cut, the exposed paste needs direct protection even though the exterior already carries a coating.

CHECK THE LABEL
Leerdammer Original lists pasteurized milk. Keep it refrigerated, respect the package date, and follow current local pregnancy guidance.

SOURCES & REFERENCES


1.
Leerdammer, 2026 producer
Used for the 1974 origin, founders, Leerdam name and the documented Gouda and Emmental design goal.

2.
Leerdammer Nederland, 2026 producer
Used for current flavor, lactose threshold, calcium, vegetarian status, ingredients, rind natamycin and nutrition values.