What Does Poaching Fish in Milk Do? The Science and Benefits Explained

Poaching fish in milk rather than water or stock may sound unusual, but it actually has some major benefits. The milk helps the fish retain moisture, adds flavor, and creates a luscious, creamy sauce. Read on to understand the science behind poaching in milk and how to use this technique for tender, delicious fish.

Why Cook Fish in Milk?

There are a few key reasons why milk is a smart choice for poaching fish:

• Milk retains moisture better than water, keeping fish tender and preventing dryness. The proteins in milk help it hold onto the natural juices.

• Milk adds richness, fat, and creaminess, giving you a built-in sauce. The natural sweetness also enhances the flavor.

• Milk absorbs and amplifies other aromatics like herbs and garlic infusing them into the fish.

• The milk proteins change when heated, lightly thickening into a silky poaching liquid.

• Milk contains vitamin B12, calcium, potassium and other nutrients that get infused into the fish during poaching.

Overall, milk provides taste and texture benefits you just can’t get from water, stock or wine when poaching. Let’s look closer at the science and chemical reactions involved.

The Science of Poaching in Milk

Several things happen on a molecular level when fish is submerged and gently cooked in hot milk:

Denaturing of Proteins

Heating causes the whey and casein proteins in milk to unravel or “denature.” The proteins then link together into a network that thickens the milk slightly.

Emulsification

The fat in the milk bonds with water molecules, allowing smooth integration rather than separation. This emulsification helps create a creamy, uniform poaching liquid.

Flavor Extraction

Compounds like lactose and riboflavin in milk generate aromas and flavors when heated. Any added herbs or spices also release their essences, which the milk readily absorbs.

Collagen Transformation

The collagen in fish converts to gelatin during poaching at low heat, keeping the flesh tender and moist. Milk’s proteins support this process.

Science proves that the chemical properties of milk make it ideal for keeping fish deliciously moist and infusing it with flavor. Now let’s go over the best techniques for poaching fish in milk.

Step-By-Step Instructions for Poaching Fish in Milk

Follow these simple steps for foolproof results:

Choose an Appropriate Fish

Go for thicker, firmer fillets that will hold their shape well in milk. Salmon, cod, halibut, or tuna work best. Avoid thin, flaky varieties like sole that may overcook.

Heat Milk Gently

Pour enough whole milk in a skillet to come halfway up the fish. Slowly heat it to 170-180°F, hot but not boiling. The lower temperature keeps milk from curdling or burning.

Submerge and Poach

Gently lower fish into the hot milk, turning over once halfway through. Poach delicate fish for 4-6 minutes, thicker fillets for 6-8 minutes until opaque and cooked through.

Rest and Serve

Let the cooked fish rest in the milk another 1-2 minutes off heat. The residual heat finishes cooking. Carefully transfer fish to plates and spoon the infused milk over the top as a sauce.

That’s all it takes to let milk work its magic! Now let’s go over some pro tips and serving suggestions.

Handy Tips for Perfectly Poached Fish

• Thinner milk like 2% may curdle, so stick to whole milk. You can also use half and half or heavy cream.

• Add aromatics like garlic, shallots, herbs or citrus zest to the milk to infuse more flavor.

• Resist overcooking the fish. Check earlier and remove when opaque and flaky.

• If the milk “breaks” and curdles, use an immersion blender to fully reincorporate.

• For a thicker sauce, whisk in a bit of flour, cornstarch, or heavy cream after poaching.

What to Serve with Poached Fish in Milk

The creamy milk sauce is delicious, but try these accompaniments too:

• Rice or risotto to absorb the savory milk sauce

• Garlic mashed potatoes or creamy polenta

• Sauteed vegetables like asparagus, peas, or zucchini

• Fresh herbs like parsley, basil, or chives

• Lemon or lime wedges to brighten the flavors

• Toasted breadcrumbs or croutons for crunch

• Sharp cheeses like Parmesan or feta to garnish

Ideas for Different Types of Milk and Fish

Don’t limit yourself to cow’s milk and salmon. Mix it up with unique combinations:

• Poach cod or haddock in coconut milk flavored with Thai red curry paste and cilantro.

• Use almond milk seasoned with saffron and ginger to poach halibut.

• Poach tuna in soy milk with five-spice powder, shiitakes, and scallions.

• Infuse goat’s milk with lemon thyme and garlic to gently cook trout.

So explore beyond traditional milk and fish pairings. The world is your poaching palette!

Can You Poach in Milk Then Finish Another Way?

You sure can! Try these techniques:

• Poach in milk, then finish under the broiler or on the grill for crispy, caramelized exterior.

• Poach in milk, chill fully, then bread and pan fry for fish sticks.

• Shred poached fish after cooling and mix with creamy mashed potatoes for fish cakes.

• Flake poached fish over salad greens and drizzle the infused milk as a dressing.

Storing and Reheating Leftover Poached Fish

Properly stored leftover poached fish stays fresh 3-4 days:

• Let fish and milk cool fully, then refrigerate in an airtight container.

• Reheat gently in a skillet or saucepan over medium-low heat with a splash of milk or cream.

• Microwave single servings covered in milk to retain moisture.

• Flake into salads, tacos, fish cakes or dip in batter and fry as fish and chips.

• Freeze poached fish up to 2 months. Thaw in fridge before using.

Common Questions about Poaching Fish in Milk

Here are some frequent queries:

Does the fish flavor get into the milk?

A little, but mostly the aromatics in the milk permeate the fish, not vice versa. Any fishiness in the milk is very subtle.

Can you use skim or 2% milk to poach?

It’s better to use whole milk, half and half or cream. Lower fat milk may curdle more easily or not thicken as well.

Is poaching fish healthier than frying or breading?

Yes, poaching is one of the healthiest cooking methods. The fish retains nutrients but absorbs no added fat or oil.

What kind of aromatics work well when poaching in milk?

Herbs like thyme, parsley or tarragon, spices like garlic, pepper or saffron, or citrus zest all infuse nicely into the milk.

Is poaching fish in milk an old traditional cooking technique?

Not really – it’s a more modern, creative technique that builds on traditional poaching methods.

Master the Magic of Milk-Poached Fish

Poaching fish in milk may seem unorthodox, but once you understand the science and technique, you can master this clever cooking method. The milk acts as a flavor-infusing liquid that keeps fish deliciously moist and tender.

The key is gently heating the milk, adding aromatics, and poaching the fish just until cooked through. Experiment with different types of milks and fish fillets. Serve the fish bathed in the creamy, herb-scented poaching milk for a quick yet impressive meal. Once you try poaching in milk, you may never go back to water!