Hello everyone!
I have done a search of blog/forums for buttermilk and read very useful tidbits of information here and there, most hidden in the answers to larger baking questions.

I am researching buttermilk right now and wondered whether anyone could point to a good article, post, book chapter, etc. on the role of buttermilk in baking.

I understand generally that buttermilk is acidic and will interact with leavening differently as a result (which is why I eliminated the use of acidic lemon juice in the batter of my lemon poppyseed wedding cake recipe, in favor of lemon oil and zest in the batter). From this thread and the knowledgable Christine S., buttermilk (b/c it’s acidic) “weakens the gluten in the flour, and makes all-purpose flour behave more like cake flour in terms of gluten strength.” So it would appear that it is the acid in buttermilk that creates the wonderful tenderizing effect.

Is that the end of the story?

In Rose’s recipe for blueberry muffins , she recommends that one susbstitute baking powder for some of the soda for flavor, not for texture.  I wonder why that is?

At brunch with friends, I notice that buttermilk pancakes taste much better to me than others. Certain pancakes have a foul metallic taste in my mouth, and my theory is that I am tasting the baking soda that otherwise would have been neutralized by the buttermilk. But that theory seems to go against what Rose says in her muffin recipe above. And I trust Rose!

I love using buttermilk (and sour cream, which has similar properties) in baking, and am very interested in finding out more about how it works in the chemical reaction of baking. If anyone could point to a resource to find out more, I would appreciate it. Maybe I missed something in TCB!

Rachel

RACHEL FROM SCRATCH:
  Good afternoon to you. I have read your post with much interest. If you would like to learn about BUTTERMILK a good place to begin is to get the book called “ON FOOD & COOKING” by Harold McGee. If you do not have it try the library if they do not have it ask for “INTER~LIBRARY service…other libraries may have it & it can be loaned to your community library for your use.

  Now then Rachel you are correct that the foul taste in certain pancakes recipes is due to the excessive amount of soda that is employed. As you know soda is merely used to neutilize the acdic taste of an ingredient.  With that Rachel, you then asked about Miss Rose subst. some more powder for the soda & why that is???? It is for flavor purpose. Miss Rose likes tangy tasting desserts (Check-out
her cheesecake recipe 2.5, tons of sourcream in relation to the cream~cheese…speaking about TANGY)
Back to the buttermilk she doesn’t want to subdue the tangy taste of the buttermilk by using soda to neutilizing it. You know ...beauty is in the eye of the beholder.
  Rachel I think I am finished now I hope this helps somewhat. Enjoy the rest of the day my friend.

  ~CASS.

Rachel, a few thoughts:
- read the understanding section on the buttermilk country cake in the cake bible, it mentions that buttermilk acts as a buffer in cake batters.
- Rose also mentioned in the Bread Bake-Off (Show & Tell) that acid relaxes gluten without destroying it.
- Many recipes for pancakes call for lots of baking powder- some kinds taste metallic and shouldn’t be used.  Rumford is good, though, and I have heard that you can make your own baking powder from 2 parts cream of tartar and one part baking soda.
-As Freshkid mentions, how much to neutralize a batter is a matter of personal preference, though a highly acidic batter may not set properly and may not brown well.
-buttermilk tends to dull chocolate quite a bit, so don’t use it in a chocolate cake.

I agree with Julie that Rumford is good - I have noticed the metallic taste in butter cakes made with other brands of baking powder, but haven’t detected it when using Rumford. I’m no help with the buttermilk properties, though.

Mr Nitpick here. The metallic taste you are referring to is caused by using baking powder that contains aluminum sulfate. It provides the acid to react with the soda which provides the base to produce carbon dioxide. Its main advantage is that the reaction is less rapid and is enhanced by heat so the leavening effect is better timed.
However as you have noticed many of us myself included find the taste unpleasant. I use Rumford which does not contain aluminum sulfate.
I love to use buttermilk in bread baking it can produce some magic effects. I use it when I want to produce a more tender crumb and I find the hint of acidity that it supplies enhances many flavors.

Thank you so much everyone! This is so fun- the internet is awesome.

I am a little embarassed that I didn’t think of Shirley Corriher (the biochemist and cookbook author) since she just won the James Beard Award for her book BakeWise! And did I mention she is a biochemist? 

Someone else recommended Harold McGee’s book (“On food and cooking—the science and lore of the kitchen”) for the section on buttermilk, so I will definitely read that as well.  And I believe he is coming to Bay Area (CA, where I live) to give a talk this fall. so I better get going and read the book.

I also got a recommendation for Bakewell Cream leavening agents, which are supposed to have a milder taste. I have never seen or tried them! However, I can confirm that I use Rumford in my own baking and have for years, and I have always been very happy with it.

I have also noticed that many bakers prefer to substitute some or all of the soda called for in a recipe with baking powder. I suppose the answer to the flavor question was in my question! People most likely to do that avoid metallic aftertaste!

Rachel, I think the metallic aftertaste comes from some baking powders containing aluminum sulfate (as Gene points out), not from baking soda, which tastes sort of salty.  If people are switching from soda to powder, I think it’s because they prefer not to neutralize an acidic ingredient, i.e., they prefer tanginess in a recipe with buttermilk.

I think I have read (somewhere in Cooks’ Illustrated? Maybe in an article about cookies?) that baking soda enhances browning. I wonder if an acid batter browns less and an alkaline one browns more…

I also recall a number of references to an “unpleasant taste” in recipes that use too much baking soda. They were definitely talking about baking soda, not baking powder. I suppose you could do an experiment to find out—don’t some folks use salt and baking soda to brush their teeth? You could just taste a small amount—maybe dissolved in a little water.

If you are comparing using buttermilk to using just water, then in addition to the acidity factor, you also have a little bit of fat and some milk solids. Milk solids, as I recall, add flavor and enhance browning. Compared to milk or water, buttermilk is also thick, because of the coagulation of the milk proteins. You’re apt to get a thicker batter, though I’m not sure how much that affects the final texture of the baked good.

BUNGALOW BARBARA:
  Good morning to you.  Just to add a little non~important information. You are correct about the use of excessive soda in a baked product.
The term used amongst prof bakers is “BITTER” tasting.  However, no matter what word we use metallic or bitter or funny tasting…. too much ,  doesn’t taste very well.
  Good luck to you & enjoy the rest of the day.

  ~FRESHKID.

Hi Rachel! Here are some more tidbits to add to your growing body of knowledge on buttermilk. Paula Figoni reports in How Baking Works: Exploring the Fundamentals of Baking Science that unreacted baking soda and the remaining salt residue contribute to off flavors when high levels of baking soda are added to baked goods. The point of the acid is that it allows you to use less baking soda to produce CO2 for leavening, so there is less chance of chemical off flavors and also less discoloration.

Common acids used are your friend buttermilk plus yogurt, sour cream, fruit and fruit juices, vinegar, most syrups including molasses and honey, brown sugar, unsweetened chocolate and natural cocoa. The disadvantage to using these acid ingredients is that they can vary in acid content. Buttermilk, sour cream and yogurt in particular increase in acidity as they age. Another trait important to remember is that the acid tends to react with the baking soda right away. So you’ve got to get that batter baking immediately after mixing or the CO2 will have dissipated before baking. Result: no leavening.