Sourdough Tempura Batter

Light, Crispy, and Tangy

RECIPESDISCARD

5/29/20255 min read

Tempura might sound fancy, but let me tell you—it’s way easier than you think. And when you add sourdough to the mix? Game-changer. This sourdough tempura batter is ultra-light, perfectly crispy, and has a subtle tang that sets it apart from traditional versions. Whether you’re frying up veggies, shrimp, or even something a little unexpected (like mushrooms or pickles), this batter delivers restaurant-quality results without the stress. So grab your discard and let’s fry something magical.

Why Sourdough in Tempura?

You might be wondering: why sourdough? Why take a perfectly good Japanese technique and add tangy, fermented starter to it?

Here’s why:

Crispier Texture: Sourdough discard creates a delicate crunch that’s hard to beat.
Subtle Flavor Boost: That little tang from the ferment balances rich or earthy ingredients.
Waste Less: Got discard? Tempura is the perfect excuse to use it up instead of throwing it away.
No Fuss: No eggs or fancy steps. Just cold water, discard, and flour = pure tempura joy.

I’ve tested this recipe with all kinds of veggies, seafood, and even cheese (yep, cheese tempura is a thing), and it has never failed me.

Ingredients You’ll Need

Here’s everything you need for this ridiculously easy sourdough tempura batter:

1 cup sourdough discard (100% hydration, unfed is fine)
1/2 cup ice-cold water (really cold—ice cubes are your friend)
3/4 cup all-purpose flour
1/4 cup cornstarch (for crispiness)
1/2 tsp baking soda (optional but helps with lift)
Pinch of salt
Oil for frying (neutral oil like canola, avocado, or peanut oil works best)

Optional for Flavor Add-ins:

Garlic powder
Smoked paprika
Black pepper
Dried herbs (for veggie-forward tempura)

Keep it basic for authentic Japanese-style or spice it up if you’re feeling creative.

Tools You’ll Need

Mixing bowl
Whisk or chopsticks
Deep pan or Dutch oven
Thermometer (for oil temp)
Slotted spoon or tongs
Paper towels or a wire rack

Nothing fancy required!

Best Ingredients for Tempura Frying

The best thing about tempura is you can fry just about anything. Here are some of my top picks:

Veggies:

Sweet potato (thinly sliced)
Carrot sticks
Bell pepper strips
Mushrooms (oyster or shiitake are chef’s kiss)
Zucchini or summer squash
Green beans
Broccoli florets
Cauliflower

Protein:

Shrimp (peeled and deveined, tails on)
White fish (cut into strips)
Chicken tenders (thinly sliced)
Tofu (extra-firm, patted dry)

Wild Cards:

Pickles
Cheese curds
Apple slices (for a dessert-style tempura!)
Avocado chunks (yes, it’s dreamy)

Pro tip: Pat your ingredients dry before dipping. Water = splatter.

Step-by-Step Instructions

Step 1: Prep Your Frying Station

Before you even touch the batter, get your station ready. This means:

Fill a deep pot with 2–3 inches of oil.
Set up your thermometer (aim for 350°F/175°C).
Lay paper towels or a wire rack next to your stove for draining.

Having everything in place keeps things stress-free when the frying starts.

Step 2: Chill Your Water

Cold water is critical for tempura. Why? It slows gluten development, keeping the batter light and crisp.

Fill a glass with ice water and let it chill while you prep your other ingredients. Don’t skip this part.

Step 3: Mix the Batter

In a mixing bowl, whisk together:

1 cup sourdough discard
3/4 cup all-purpose flour
1/4 cup cornstarch
1/2 tsp baking soda
Pinch of salt

Add 1/2 cup of ice-cold water and mix gently—you want lumps! Overmixing = chewy coating. The batter should be the consistency of heavy cream. Too thick? Add a splash more cold water. Too thin? Sprinkle in a bit of flour.

If you’re adding seasoning, do that here. But keep it light—tempura is all about balance.

Step 4: Dip & Fry

Once your oil hits 350°F, it’s go time.

Dip your veggie, shrimp, or whatever into the batter.
Gently drop it into the oil (away from you, please!).
Fry for 2–3 minutes, turning if needed.
Remove once golden and crispy.

Drain on a rack or paper towel. Repeat in batches so you don’t overcrowd the pan.

Step 5: Serve It Hot

Tempura is best immediately after frying. That’s when it’s peak crispy and glorious. Serve with a simple dipping sauce (recipe below), rice, or a light salad.

Simple Dipping Sauce (Tentsuyu Style)

1/2 cup soy sauce
1/2 cup water
2 tbsp mirin
1 tsp sugar
Optional: grated daikon or a splash of rice vinegar

Simmer everything together until warm. That’s it. This dipping sauce is savory, balanced, and pairs beautifully with the tang of the sourdough.

Tips for Tempura Success

1. Keep your batter cold. You can even keep it over a bowl of ice.

2. Don’t overmix. Seriously—lumps are fine.

3. Use fresh oil. Old oil = funky flavor.

4. Fry in small batches. This keeps the oil temperature stable.

5. Eat immediately. Tempura doesn’t age well. It’s a crispy moment worth savoring hot and fresh.

Sourdough Tempura FAQ

Can I use active sourdough starter instead of discard?
Totally! It’ll give a slightly more complex flavor and even more airy texture.

Can I make it gluten-free?
Yes. Swap all-purpose flour for a gluten-free flour blend and use cornstarch as usual. Make sure your sourdough discard is from a gluten-free starter!

What oil is best for tempura?
Neutral oils with a high smoke point are best. Canola, peanut, or avocado oil are great.

Can I reuse the frying oil?
Yes—but strain it through cheesecloth once it cools, and don’t use it more than 2–3 times.

How do I store leftovers?
Tempura is best eaten fresh, but you can store leftovers in the fridge for a day and re-crisp them in the oven at 400°F for a few minutes.

Serving Ideas

Looking for ways to make your tempura shine? Try these:

Tempura Donburi (Bowl): Serve over steamed rice with dipping sauce.
Tempura Tacos: Yup—tempura shrimp or cauliflower in a tortilla with slaw and spicy mayo.
Appetizer Platter: Pair with dipping sauces, pickles, and fresh herbs.
Tempura Sushi Rolls: Use leftover tempura for inside-out rolls.

Flavor Twists

Here’s how to play with the flavor profile while keeping the same technique:

Spicy Sourdough Tempura: Add chili flakes or cayenne to the batter.
Herby Twist: Stir in finely chopped parsley, dill, or chives.
Lemon Tempura: Add lemon zest for a citrusy vibe that’s great with seafood.
Garlic-Lovers Tempura: Add garlic powder and black pepper.

Let’s Talk Texture

What makes sourdough tempura different from the usual? It's all about that beautiful balance between airy and crunchy. The discard gives the batter a little body, while the cornstarch ensures things stay snappy. The result is tempura that feels almost delicate in your mouth—crispy on the outside, light and flavorful on the inside.

Frying Troubleshooting Guide

Tempura too greasy?

Oil too cold. Make sure you’re hitting that 350°F sweet spot.

Batter falling off?

Dry your ingredients better before dipping.
Batter might be too thin. Add a spoonful of flour.

Too chewy?

Batter was overmixed or rested too long. Mix gently and fry immediately.

Oil smoking?

It's too hot! Reduce heat and use a thermometer.

A Love Letter to Sourdough Discard

If you’ve been baking sourdough for any length of time, you know the discard struggle is real. Tossing it feels wasteful. But finding cool ways to use it? That’s where the magic is.

This tempura batter is one of my favorite sourdough discard recipes because it:

Feels gourmet without the effort
Uses basic ingredients
Comes together in 5 minutes
Turns your kitchen into a crunchy wonderland

So next time you’re eyeing your jar of discard and wondering what to do—tempura. Always tempura.

Final Thoughts

This sourdough tempura batter is a golden ticket to crispy, flavorful goodness—no matter what you decide to fry. It’s quick, it’s easy, and it’s proof that sourdough discard can be used for way more than just pancakes or crackers.

Whether you’re throwing together a fun appetizer, planning a tempura night with friends, or just need a little crunchy joy in your life, this recipe has your back.

So go ahead—batter up and fry something beautiful.