The Secret In-N-Out Sauce: A Homemade Copycat Recipe

Do not be misled by those fancy burger places – making their special sauces is actually a lot easier than you might assume. Even more exciting, you likely have a lot of the required items already in your fridge.

If not, they are super easy to find at any grocery store. Here's what makes this sauce work.

• Mayonnaise: Regular or light mayonnaise both work effectively, offering that signature smooth, spreadable texture. Premium brands like Hellmann's or Best Foods deliver superior results with their balanced flavor and ideal consistency.
• Ketchup: Go for a good quality ketchup. The ketchup does double duty here - it gives the sauce that signature pink color and adds a sweet-tangy kick that makes the sauce pop. The natural tomato flavor really comes through and makes a difference.
• Vinegar: A small amount of white vinegar adds essential brightness. Starting with just a teaspoon allows for proper flavor development while maintaining control over the final tang level. White vinegar's clean, sharp flavor works perfectly without introducing competing tastes.
• Sweet Pickle Relish: This is the game-changer. Those tiny bits of sweet pickles add texture and bright pops of flavor in every bite. The sweet-sour punch from the relish is what makes this sauce taste like the real deal. Don't skip this - it's essential.
• Yellow Mustard: Many sauce enthusiasts believe yellow mustard is the secret component in the original sauce. This humble condiment adds depth and a subtle warmth that transforms the sauce. The natural emulsifiers in mustard also help create a smoother, more stable sauce.
• Granulated Sugar: This optional ingredient helps balance tanginess when needed. Some prefer the sauce without added sugar, especially when using sweet pickle relish. The beauty of making this at home means adjusting or omitting sugar based on personal preference.

West Coasters will know and love In-N-Out and their burgers are so famous but it’s the sauce that puts them over the top.

This isn’t rocket science; making this signature sauce at home is easy. Check out this detailed guide to recreate this beloved sauce in your kitchen.

Ingredients

• 1/2 cup mayonnaise
• 3 tablespoons ketchup
• 2 tablespoons sweet pickle relish
• 1 teaspoon white vinegar
• 1 teaspoon granulated sugar (optional)
• 1 teaspoon yellow mustard (or more as per taste)

Instructions

Step 1: Prepare Your Workspace

Begin by creating a clean, organized workspace in your kitchen. Pull out a medium-sized mixing bowl - glass or stainless steel both work great. Take time to measure all ingredients accurately before starting.

Room temperature ingredients blend much better, so let the mayo sit out for about 15-20 minutes if it's straight from the fridge.

Having everything ready prevents rushing and ensures consistent results. A rubber spatula works best for mixing, but a wooden spoon works too.

Step 2: The Foundation

Pour your measured mayonnaise into the mixing bowl. Using smooth, deliberate strokes, start adding the ketchup gradually. This careful addition helps prevent any lumps from forming.

Mix until you achieve a uniform peachy-pink color throughout - this usually takes about a minute of steady stirring. Make sure to scrape the sides of the bowl as you go to catch any unmixed mayo hiding there.

This base mixture should be completely smooth before moving forward.

Step 3: Add the Flavors

Time to layer in those essential flavors. First, check your sweet pickle relish - if it appears watery, drain it in a fine mesh strainer. Or press it gently between paper towels. Too much liquid can give your sauce runny texture.

Add the drained relish to your mayo-ketchup base. Next comes the yellow mustard - start with one teaspoon. Add your first teaspoon of white vinegar.

The order matters here because it lets you adjust the tangy elements properly. Mix everything together using folding motions to distribute the relish evenly throughout the sauce.

Step 4: Taste and Adjust

This important step requires attention to detail. Take a small taste of your sauce and allow it sit in your tongue for a second. Think about the balance of flavors.

Need more tang? Add a few drops of vinegar at a time, mixing and tasting between additions. If you want extra depth add another quarter teaspoon of mustard.

If the sauce tastes flat, this is when you'd add sugar - but just a little at first. Some people prefer it without any added sweetness, letting the natural sweetness of the relish shine through. Keep adjusting until everything tastes harmonious.

Step 5: The Final Mix

Once you're happy with the flavor balance, give the sauce a thorough final mixing. Use your spatula to fold the mixture over itself repeatedly, making sure those bits of relish are evenly distributed throughout.

Scrape down not just the sides but also the bottom of the bowl - unmixed ingredients often hide there. The sauce should look uniform with visible specks of relish throughout.

Step 6: The Waiting Game

Transfer your finished sauce into a clean container with an airtight lid. Glass jars or plastic containers both work well, just make sure the lid seals properly.

Let the sauce rest in the refrigerator for at least one hour, though overnight brings even better results. This resting duration is important - it allows all those flavors to meld together and develop completely.

The sauce would possibly appear a bit loose at first, but it will thicken slightly as it chills. Give it a quick stir before using.

• Room Temperature Mixing: Let refrigerated items sit out for 20-30 minutes before mixing. Cold components, especially mayonnaise, tend to stay lumpy and do not blend smoothly. Room temperature ingredients create a silkier, more uniform sauce.
• Drain The Relish: The extra liquid of sweet pickle relish can make your sauce watery. Put the relish in a fine mesh strainer or wrap it in cheesecloth and give it a little gentle squeeze. It takes the extra moisture out of the pickle bits without ruining all their flavor.
• Season in Stages: Add vinegar and mustard gradually, tasting between additions. Once added, these strong flavors can't be taken out. Start with half the recommended amount, then adjust upward. This method ensures better control over the final taste.
• Quality Matters: While generic brands work fine for most ingredients, splurge on good mayonnaise. Brands like Hellmann's or Best Foods make a noticeable difference in the final texture and taste. Their balanced flavor and creamy consistency create a better foundation for the sauce.
• The Sugar Test: Before adding sugar, let the mixed sauce sit for 5 minutes. The relish's sweetness develops more fully after a brief rest. Taste again - you might find you need less sugar than expected or none at all. This prevents an overly sweet sauce.
• Double Batch Benefits: Making a double batch? Mix each batch separately, then combine them. This ensures more consistent seasoning and better texture control. Plus, the sauce actually gets better after 24 hours in the fridge, so extra sauce means better burgers tomorrow.

That creamy, tangy sauce you just whipped up isn't just for burgers. Sure, slathering it on a Double-Double copycat is amazing, and yes, dipping hot, crispy fries in it is practically mandatory.

However, this versatile sauce can turn ordinary everyday foods into something truly special. Here are some fantastic ways to put your self made sauce to work.

• Classic Burger Spread: Start with the obvious - spread it generously on your burger buns. The sauce seeps into those toasted buns, making every bite better. Pro tip: spread it on both buns for maximum flavor, and don't be shy about adding extra on the side for fry-dipping.
• French Fry Dip: Hot, crispy fries and this sauce are a match made in heaven. The cool, creamy sauce perfectly balances hot, salty fries. Try it with sweet potato fries too - the sauce's tang cuts through their sweetness beautifully.
• Sandwich: Transform these healthy sandwiches into something special. Works great on cold cuts, grilled chicken, or even veggie sandwiches. The sauce adds moisture and zip to basic lunch meat, making even simple turkey on wheat taste restaurant-worthy.
• Onion Ring Companion: Forget plain ketchup - this sauce takes crispy onion rings to new heights. The sweet tangy combo complements the onion's natural sweetness while cutting through the breading's richness.
• Veggie Dip with a Twist: Raw vegetables get an upgrade here. Carrots, celery, bell peppers, cucumber slices - they all taste better with this sauce. Perfect for afternoon snacking or party platters. The sauce's creaminess makes eating those vegetables actually enjoyable.
• Grilled Chicken Topping: Brush some on grilled chicken in the last few minutes or so of cooking or use as a dipping condiment. Plain chicken breasts are brightened by the sauce's tanginess, preventing them from being bland.
• Ultimate Potato Enhancer: You don't have to stick to ordinary fries. It’s good on hash browns, home fries or if you’ve roasted potato wedges. Something about potatoes and this sauce simply works - specifically when the potatoes are hot and crispy.
• Secret Salad Dressing: Thin it out with a little milk or buttermilk. And you get a unique salad dressing. Works especially well on chopped salads or as a drizzle over wedge or spinach salads. The sweet pickle bits in the sauce add unexpected bursts of flavor to each bite.

Making extra burger sauce saves precious time in the kitchen. A larger batch means not having to mix small portions every time burger cravings hit. But proper storage is key to maintaining that fresh, creamy taste everyone loves.

Refrigerator Storage

Clean glass containers work best for storing this sauce. Transfer the sauce into the container and leave a small gap on the top. Make certain the lid seals tightly to prevent any air from getting in.

The sauce stays fresh in the fridge for about a week. The mixture might become slightly thick when cold, which is perfectly normal. Simply remove from the refrigerator 10-15 minutes before serving and stir well before use.

Freezer Storage

Freezing the sauce is certainly possible, but it is not recommended. When frozen and thawed the mayonnaise base tends to separate and become grainy. The smooth, creamy texture changes significantly.

Anyone wanting to freeze the sauce anyway should use small, airtight containers and freeze for no longer than 2 months. Smaller portions work better since the sauce can only be thawed once.

When ready to use, thaw overnight in the refrigerator (never on the counter). After thawing, the sauce requires thorough whisking to recombine the elements.

Adding a few drops of water helps obtain the proper consistency, although the texture may not be precisely like fresh sauce.

Quick tip: Always label your container with the date. You'll thank yourself later. And remember, if you see any odd colors or smell something off, don't chance it – just make a fresh batch.