How to Marinate Properly: What Actually Penetrates Meat?

Marinating might seem like one of the simplest cooking techniques - mix a flavorful liquid, add your meat, let it soak, and cook. Easy, right? Yet despite how common it is, marinating is one of the most misunderstood steps in home cooking. Many people imagine their marinade traveling deep into the meat, flooding it with flavor and tenderizing it from the inside out. But the truth is far more interesting, and understanding how marinades actually work can instantly improve your cooking, help you avoid common mistakes, and make your food juicier, more flavorful, and much more consistent. When you know what penetrates meat (and what doesn’t), you’ll marinate with purpose - not just hope.

At its core, a marinade is a mixture of acid, salt, fat, aromatics, and sometimes sugar, each playing a very specific role. But not all components behave the same way. Some penetrate deep; others stay near the surface; some tenderize; others simply season. For example, acids like vinegar, citrus juice, yogurt, and wine don’t travel deep into proteins. Instead, they work only on the surface, loosening and denaturing outer proteins. This is why overly acidic marinades can make the outside of meat mushy while the center remains completely untouched. People often leave meat in lemon juice overnight expecting deep tenderizing, but acids mostly act on the first millimeter. So, if your goal is deep flavor, relying on acid alone won’t get you there.

Salt, on the other hand, is the real hero when it comes to penetration. Unlike big flavor molecules (herbs, garlic, spices), salt is small enough to move into the meat, and it travels slowly but surely. This is why salt-based marinades - or better yet, brines - are so effective. When salt enters the muscle fibers, it dissolves some proteins, allowing them to hold onto more moisture. That means the meat retains more juice during cooking and becomes more tender without turning mushy. Salt also carries some water-soluble flavors with it, but only if those flavors are small enough to hitch a ride. This is why soy sauce - a salty, umami-rich liquid - is such a powerhouse marinade ingredient: its components (salt, glutamates) truly move inward, building deeper savoriness.

Meanwhile, aromatics like garlic, rosemary, ginger, and herbs contribute incredible fragrance, but they don’t penetrate deeply. Their flavor molecules are simply too large to travel through muscle fibers. Instead, they perfume the surface, creating intense outer flavor while leaving the interior neutral. This is why marinating is still valuable: even surface-level flavor makes a huge difference, especially when the meat is grilled, roasted, or pan-seared. The key is understanding that aromatics build exterior character, while salt builds internal seasoning.

Fat in marinades - whether from olive oil, yogurt, coconut milk, or sesame oil - helps distribute fat-soluble flavors and carry them onto the surface of the meat. Fat doesn’t penetrate either, but it clings, protecting the surface from drying and helping fats and spices stick during cooking. This is especially important for grilling, where fat-based marinades help the meat brown beautifully and develop a more delicious crust. Sugar, meanwhile, plays its own role: it encourages caramelization, helping grilled and roasted foods achieve that beautiful golden exterior. It also balances acidity and enhances overall flavor.

One of the biggest misunderstandings is how time affects marinades. Many people assume longer is always better, but in reality, most marinades don’t need more than a few hours - especially acidic ones. Chicken breasts, for example, can become chalky if left in acidic marinades for too long. Fish can start to “cook” ceviche-style in under an hour. On the other hand, salt-forward marinades can go longer because the salt penetration happens slowly and gently.

A general guideline is:

• Fish: 15-45 minutes

• Chicken breasts: 1-2 hours

• Chicken thighs/drumsticks: 3-6 hours

• Pork chops: 2-6 hours

• Pork shoulder: 6-12 hours

• Beef steaks: 2-12 hours, depending on thickness

• Tough cuts like flank, skirt, brisket: 6-24 hours, mainly for surface flavor and salt penetration

These ranges allow salt to work effectively while preventing acids from damaging the surface.

If your goal is deep, even seasoning, dry brining - rubbing meat with salt and letting it rest in the refrigerator - is often more effective than traditional marinating. Salt moves farther into the meat without the risk of diluting flavor or washing away the natural juices. You can then add surface flavors later through a quick marinade, spice rub, or glaze. Many chefs rely on this two-step approach: salt first, flavor second. Once you try it, you’ll understand why your meat becomes dramatically more flavorful and juicy.

Another important detail is that marinades can’t overcome the structure of certain meats. Very tough cuts like brisket or chuck won’t be tenderized by acid or oil. They require slow cooking or braising. Marinades can enhance flavor, but they won’t magically soften tough connective tissue. Similarly, very lean meats won’t absorb fat or aromatics deeply. They simply don’t have the structure to soak up those ingredients. This is why choosing the right technique matters: marinate meats with relatively open grain (like flank steak), dry brine thick cuts, and slow-cook collagen-rich pieces.

Of course, technique matters as much as formula. Always pat your meat dry before cooking - even if you marinated it. Excess marinade causes steaming rather than searing, which prevents browning. Browning is where much of the flavor happens, and a dry surface is the secret. You can brush the remaining marinade onto the meat during cooking for added flavor, but start with a dry surface for the best crust, especially when grilling or pan-searing.

In the end, proper marinating isn’t about soaking meat and hoping for magic. It’s about understanding the chemistry of flavor. Salt penetrates. Acids tenderize only the surface. Aromatics stay outside, creating a delicious crust. Fat helps carry and balance flavors. Once you know what actually happens beneath the surface, you can customize your marinades to get exactly the results you want - juicy chicken, deeply seasoned steak, fragrant grilled vegetables, or perfectly balanced seafood. Instead of guessing, you’ll marinate with intention, confidence, and a much deeper appreciation for what’s happening in those few simple ingredients.

When you marinate properly, you unlock meals that taste fuller, richer, and more complex - whether you’re cooking for a weeknight dinner or impressing guests with your grilling skills. It’s a small technique, but done right, it makes everything you cook taste better.