What is Buttermilk? Baking's Secret Ingredient Explained
Complete guide to buttermilk - what it is, why recipes need it, easy substitutes, and the science behind tender biscuits and fluffy pancakes
Chef Steven Harty
Professional Chef
30+ years experience
30+ years professional experience, trained under Rick Bayless. Specializes in precision cooking.
Education
Culinary Training under Chef Rick Bayless
Quick Answer
Buttermilk is fermented milk with tangy flavor and thick texture. Its acidity activates baking soda, creating tender, fluffy baked goods. Modern buttermilk is cultured milk, not leftover from butter-making.
Understanding Buttermilk
Modern Buttermilk
Today's buttermilk is low-fat milk with added bacteria cultures (like yogurt). Creates tangy flavor and thick texture. Not actually related to butter anymore.
Traditional Buttermilk
Historically, buttermilk was the liquid left after churning butter from cream. Thin, slightly sour. Rare today - most store buttermilk is cultured.
The Science
Lactic acid from bacteria cultures does two things: tenderizes gluten and activates baking soda. Result: Tender, fluffy baked goods with subtle tang.
Why Recipes Call for Buttermilk
Chemical Reaction
- • Creates lift and fluffiness
- • Makes tender crumb
- • Adds subtle tangy flavor
- • Extends shelf life
What Buttermilk Does
Recipes That Need It
Buttermilk Substitutes (5 Methods)
Milk + Acid (Best)
Best1 cup milk + 1 tbsp lemon juice OR vinegar
Stir, let sit 5-10 minutes
Works for: All baking recipes
Milk + Cream of Tartar
1 cup milk + 1¾ tsp cream of tartar
Mix well, use immediately
Works for: Baking (not marinades)
Plain Yogurt + Milk
½ cup yogurt + ½ cup milk
Thin to buttermilk consistency
Works for: All recipes, adds probiotics
Sour Cream + Milk
½ cup sour cream + ½ cup milk
Whisk smooth
Works for: Baking, dressings
Kefir (Direct Sub)
Use 1:1 ratio
Already tangy and cultured
Works for: Everything, best substitute
⭐ Quick Emergency Sub: 1 cup milk + 1 tbsp white vinegar. Let sit 5 minutes = instant buttermilk!
Best Buttermilk Recipes
Southern Buttermilk Biscuits
- 2 cups flour
- 1 tbsp baking powder
- ½ tsp baking soda
- 1 cup cold buttermilk
- 6 tbsp cold butter
Makes: 8-10 fluffy biscuits
Buttermilk Pancakes
- 2 cups flour
- 2 tbsp sugar
- 2 tsp baking powder
- 1 tsp baking soda
- 2 cups buttermilk
- 2 eggs
Makes: 12-14 pancakes
Ranch Dressing
- 1 cup buttermilk
- ½ cup mayo
- ½ cup sour cream
- Herbs and garlic
Makes: 2 cups dressing
Buttermilk Fried Chicken
- Chicken pieces
- Buttermilk for marinating
- Flour + seasonings
Secret: Buttermilk marinade 4-24 hours
The Science of Buttermilk Baking
pH Level: 4.5 (acidic)
Compared to: Regular milk pH 6.7
What Happens:
- 1. Acid weakens gluten proteins
- 2. Gluten can't form tight networks
- 3. Result: Tender, not tough baked goods
With Baking Soda:
- 1. Acid + Base reaction creates CO₂
- 2. Bubbles get trapped in batter
- 3. Heat expands bubbles
- 4. Creates fluffy texture
Bonus Benefits:
- • Browning (acid + heat = Maillard reaction)
- • Moisture retention
- • Longer shelf life (acid inhibits mold)
- • Rich flavor complexity
Storage & Shelf Life
🧊 Refrigerator
- • Unopened: Use by date (2-3 weeks)
- • Opened: 2 weeks after opening
- • Shake before using (separates naturally)
- • Smell test: Extra sour = still okay!
- • Thickening over time is normal
❄️ Can You Freeze It?
- • Yes! Freeze up to 3 months
- • Pour into ice cube trays (2 tbsp each)
- • Thaw in refrigerator overnight
- • Shake well after thawing
- • Best for baking (texture changes slightly)
📦 Buttermilk Powder
- • Shelf-stable alternative
- • Mix with water as needed
- • Lasts 2-3 years in pantry
- • Great for occasional bakers
- • Saco brand is popular
Frequently Asked Questions
What is buttermilk used for?
Buttermilk is used in baking (biscuits, pancakes, cakes) to activate baking soda and tenderize gluten. Also used for marinades (fried chicken), salad dressings (ranch), and adding tangy flavor to recipes.
Can I use regular milk instead of buttermilk?
Not directly - you'll lose the leavening action and tenderizing effect. Make a substitute by adding 1 tablespoon lemon juice or vinegar to 1 cup milk, let sit 5-10 minutes, then use as buttermilk.
What is the best substitute for buttermilk?
Milk + acid (1 cup milk + 1 tbsp lemon juice or vinegar) is easiest and works for all recipes. Kefir is the most similar product and can be used 1:1 without modification.
Does buttermilk go bad?
Yes, but it takes longer than regular milk due to acidity. It naturally smells tangy and sour, so use the date on the container. If it smells excessively sour, has mold, or unusual texture, discard it.
Why is it called buttermilk if there's no butter?
Traditional buttermilk was the liquid left after churning butter. Modern buttermilk is cultured low-fat milk with no butter connection, but the name stuck from historical use.
Chef Steven Harty
Professional Chef | 30+ Years Experience
Chef Harty brings over 30 years of professional culinary experience, having trained under renowned chef Rick Bayless. He specializes in precision cooking and measurement accuracy, ensuring all our cooking conversions and ingredient calculations are tested and verified in real kitchen conditions.
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