Science of Chemical Leaveners… and a Muffin

It feels like eons since I have posted a “Science of…” Post.


Granted, I have only posted two posts of this kind before (here and here), it was my goal to periodically delve into the science of baking and ask Why?

As bakers, what would we do without leaveners?


Make flatbreads?


Sure, they are good but we all need fluffy, gassy bread too.


It goes without saying (although I’m sayin’ it now) my favorite leavener is yeast (we’ll talk about that little creature some other time) but it’s slow in the gas production…


BUT my favorite book in the kitchen, On Food and Cooking, the Science and Lore of the Kitchen, recently taught me how chemical leaveners work and I’m thinking they’re pretty cool too.  I’m also wishing I would have paid more attention in all those chemistry classes I took.  Don’t worry, I’m not going to make you look at a whole bunch of chemical equations because frankly, that’s why I became a microbiologist (fun science without the equations)!


Chemical leaveners give us the fast gas production needed for cakes, quick breads, muffins, pancakes, and waffles by taking advantage of a reaction between acidic and alkaline compounds to produce carbon dioxide.  Some of these reactions occur immediately upon combining the acids and bases together and some require heat to get the reaction started.


Baking Soda aka Sodium Bicarbonate

This is an alkaline compound that can work alone as a leavener in a recipe if there is an acid in there too like yogurt, buttermilk or chocolate.  Keep in mind a 1/2 t. baking soda is neutralized by 1 c. milk, 1 t. lemon juice or 1 1/4 t. cream of tartar.  The reaction with baking soda occurs immediately upon mixing which is why these quick recipes calling for baking soda should be mixed just until combined and then baked right away.


Baking Powder

Baking Powders are a complete gassy reaction in a can just waiting to hit some moisture and heat!  I use a double-acting that contains Sodium bicarbonate, Sodium Aluminum Sulfate (SAS) and Monocalcium Phosphate (MCP) along with some cornstarch.  The cornstarch prevents premature reactions in humid air by absorbing the moisture (not a problem in Denver) and gives the powder a little more bulk for ease of measuring.  The SAS is a slow releasing reaction once heated.  The MCP is an immediate reaction that occurs during mixing.  Hence, the double-action.  Even with baking powder part of the lift that occurs is immediate so getting the batter in the oven quickly is important.


To demonstrate the use of chemical leaveners I chose a lemon poppy seed muffin.  To help with this demonstration, one of my Christmas gifts came in handy.

I got a lovely Penzey’s Baking Set for Christmas and in addition to the cinnamon, vanilla, cloves, and ginger, I got Minced Lemon Peel and Blue Poppy Seeds.  It came with a little recipe book and this recipe was included.


Notice that the lemon and yogurt neutralize the sodium bicarbonate in the baking powder creating a quick reaction upon mixing.  The MCP creates an initial reaction upon mixing.  The SAS creates a lift during the baking process.  So in this recipe there are three opportunities for gas production.


Print this Recipe


Penzey’s Lemon Poppy Seed Muffins


makes 24 muffins


1 1/4 c. granulated sugar (adjusted from 1 1/2 c. sugar for sea level baking)

1/2 c.unsalted butter, room temperature

1 T. vanilla extract

1 t. lemon or lime extract

4 eggs

1 t. penzey’s minced lemon peel (rehydrated with 1 T. water)

1/2 c. vanilla greek yogurt or sour cream

1/4 c. penzey’s blue poppy seeds

2 c. all-purpose flour

2 t. baking powder

1/2 t. salt

3/4 c. milk


Pre-heat the oven to 350 degrees Fahrenheit.  Line 24 muffin liners in two muffin papers.  Sift the flour, baking powder and salt together and set aside.  Beat the sugar and butter together until creamy.  Add the extracts and eggs and beat until fluffy.  Mix in the lemon peel, yogurt and poppy seeds.  Beat in the flour, alternating with the milk.


Fill the cupcake liners 2/3 full and bake for about 18 to 20 minutes (a few minutes longer if at sea level) or until firm to the touch.  Let cool completely before serving or storing.

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