Science Fair Project: The effect of leavening ingredients on bread

'tis almost the season...now you're talking about matzoh..

Harriet & critters

Since she has already researched how CO2 is produced, it seems that the basic design of the experiment is flawed. First of all, the inclusion of yeast is inconsistent for two reasons. First, it is not a chemical leavening agent. Secondly, it is not used properly as compared to the chemical leavening agents since you are not allowing any time for CO2 to be produced by the yeast. In other words, you have all too many variables to the experiment and any findings will be inconclusive. If she were older, I would suggest finding some additional chemical leavening agents to compare, but this would add too much complexity.

The second issue relates to your (her) assumption that the combination of baking soda and baking power will have the best results. Unless there are acidic ingredients, the baking soda will just sit there and produce no additional CO2. This indicates that neither of you really understand how CO2 is produced by chemical leavening agents.

A more easy to understand and therefore more educational comparison would be to make the recipe with no leavening agent, with baking soda only, and with baking powder only. The first to batches should be the same - flat. This would show that baking soda ALONE is not a leavening agent. The batch with baking power should be normal, thus proving you need both an acid and baking soda (aka BAKING POWDER) for CO2 production. An extension to the experiment would be to use increasing quantities of baking powder and use some objective measure like density to measure the optimum amount of baking power per unit of batter. There is a point where too much leavening agent will cause the product to collapse and become more dense, not less.

Well, the cool thing is that while she was working on the research, we were able to discuss the new info she learned about "leavening" and comapre that to "unleavened bread" eaten at Passover. The light bulb came on! Neverheard of cinnamon-raisin-oatmeal matzoh, though. Think ours might be pretty gross!

Ummm, the child is 9. I thought it was pretty good that she was able to identify that yeast is another ingredient used to leaven breads. The only variable is that she is changing the leavening agent. She will subsititute 2 t of yeast for the 1 t each of soda and powder in the original recipe. She will see why it doesn't work, and she will learn that yeast leavens differently that soda or powder. There really is no other variable in effect here. Her science teachers agreed that this was an entirely appropriate experiment for a 4th grade. This is not a college-level organic chem class. Its the elementary school sciecne fair, and a kid whose mom cooks and bakes, thus a fun project to try, emulating Mom.

Again, this is a fourth grade. It is not MY assumption, it is HER hypothesis. A hypothesis for a science fair project is simply a theory to be tested. How many fourth graders have a deep knowledge of how CO2 is produced by chemical leavening agents? My knowedge has zip, zilc, zero to do with this. Amazingly enough, I'm a mom who is actually making HER do her own science fair project and see what she can learn. My knowledge does not come into play here. The purpose of the science fair is for a child to deisgn an experiment and then to perform it. They analyze the results and gain new knowledge based on what happens. The purpose of her experiment os so she CAN learn more about how leavening agents work. Not to mention that since the original recipe calls for a combo or soda and powder, it's probably a good hypothesis.

I disagree that it would be more educational to bake only variations on the bread and never follow the original recipe we are using. What would she learn from that? The purpose of comaprison is to have 1 loaf that comes out exactly as it sould, following the recipe to a T, and then vary the recipe to see what happens. Without 1 loaf made exactly as directed, we have no 'control' to compare to.

You do realize that most 4th grade science fair experiments consist of putting food coloring into a vase with a carnatin and seeing the flower absorb the color? This one she came up with is perfectly appropriate for a little kid. perhaps a high school students with many more years of sceintific experimentation would be interested in the advanced ideas you propose, but not a little kid.

Well, there are many ways to leaven thing including steam. You ignored my points. First you are mixing various types of leavening agents - chemical and biological. Second, you are not making a meaningful comparison since you aren't letting the yeast work. Exactly what does the experiment prove other than that not allowing the yeast to ferment is not an valid way to leaven baked goods? It doesn't compare the leavening ability of yeast vs. baking powder. It just illustrates that not following directions is a recipe for failure.

The

Except that baking SODA is not a leaving agent. It is PART of a system that requires an acid. Baking POWDER is a complete system and is a leavening agent. Also, all leavening agents only work in a specified range of temperature and over a specified time. By not giving sufficient time for the yeast to ferment you have designed a flaw in the protocol. Again, it makes no sense to say that a particular agent is inferior when you design a system that guarantees failure.

She will

No, she will see that it doesn't work but there is no clear reason WHY it doesn't work because you haven't design the experiment to include TIME as a variable. The only conclusion one could make was that yeast isn't a leavening agent. In fact, one could argue that the yeast might be dead since you have no control to prove otherwise. Again, this starts to get way too complex for a 9 year old so why clutter the system with meaningless comparisons? A more fair comparison would be to add the yeast to one batch and the baking powder to another and bake-off a portion a set intervals. Given enough samples over a long enough period of time you would see that the leavening properties of baking power diminishes and the leavening power of the yeast increases with time.

There really is no

See above. You are obviously wrong.

Her science teachers agreed that this

And of course, a 4th. grade teach is the ultimate authority on science. That's why all the very brightest students can be found majoring in education leaving the slackers to study physics, mathematics, chemistry, engineering, medicine, etc. Oh, wait, it was just the opposite when I attended college.

This is not a

This would be an experiment for inorganic chemistry. When you mix in the yeast, you would have to take it to biochemistry.

Its the elementary school sciecne

Oh, sorry. I thought this was about science, not emulating mom. I also didn't realize that having fun and being logical were incompatible concepts.

Sorry, when you said that she researched how CO2 was produced, I took your word for it. Maybe you meant something else?

My knowedge has zip, zilc,

First, you didn't post the original recipe. Secondly, I find it inconsistent to first argue that the girl is young and naive and then to insist that she will be able to learn anything from a muddled experiment. I have suggested a couple of ways to simplify the experiment so one can draw clear conclusions that are explainable. And, while you claim that the girl is on her own, she is using YOUR recipe - one that uses two potential leavening agents, thus mudding the waters. I agree that the experiment is your daughter's, I think that as a parent you could ask questions and be part of a discussion that could guide your daughter. I guess that some people see parenting as a hands-off endeavor.

The "original recipe" is the first in a chain of errors. Unless your daughter found this recipe herself, you have interjected yourself into the process and therefore can not claim an "arm's length" relationship.

What would

At this point it is impossible to tell. That is my point. In addition, we have no idea if the baking soda in the "original recipe" is included as a leavening agent or as a way to increase browning, enhance gluten formation, or to modify the flavor. You have made the assumption that baking soda is always a leavening agent- but it isn't. See, the recipe is inappropriate to test your daughter's hypothesis.

Your premise about the flowers doesn't support your argument about appropriateness of your daughter's project. You also ignored all my points that explained why the experiment isn't appropriate because it introduces too many concepts and leads to no clear conclusions.

perhaps a high school students with many more years

That's the point. Unless you streamline the experiment, it would take an older student to design and execute the experiment, analyze the data, and compose a logical discussion of the data.

I'm not mixing anything,

Second, you are not making a meaningful comparison since

I'm not making any comparisons.

Exactly what does the experiment prove

Well, that's new knowledge for her. Shame, shame, she learned something today!

It doesn't compare the leavening ability of yeast vs.

What a terrible concept for a 9 year old to learn. Especially in relation to baking.

Most 9 year old kids kow that, right? Maybe you should write World Book and criticize them - that's where she found info about baking soda as a leavening agent.

It is PART of a system that

Or, perhaps, her conclusion (that yeast cannot simply be substituted for pwder or soda, but must be handled differenly) was erronious? Seeing as how that's a different conclusion than the ONLY one that exists.

In fact, one could argue that the yeast might be dead

The recipe as written is the control.

Again, this starts to get way

Kids have to start somewhere. Most leaning starts off at the beginning, then gets more challenging. She was interested in this project, that means she is actually enjoying her schoolwork at an appropriate level for her. Shocking. I should be flogged, tarred, and feathered for allowing my child to design her own sciencde fair project and see what happens, then discuss it with her to help her process her results and learning.

A more fair comparison would be to add the yeast to one batch

I'll be sure to tell her teacher, who agreed that there was 1 independent variable in this experiment. The leavening agents. Want to post your phone number, in case the teacher has any questions about why you disagree?

For a 4th grade student, yes. She obviosly knows far more than you about what is age-appropriate for a child.

And that's why all the physics majors and chem majors can be found sequencing curriculum and knowing just what is developmentally approprite for children, right?

Standard curriculum for the 4th grade in any state, as we all know.

You're right; it was terribly illogical of my child to think that she could come up with a theory and test it out, them learn from what she did.

I meant what research is in 4th grade - she read the encyclopedia and checked a few websites. She learned about bubbles causing rise. How many other 4th graders could tell you that's why bread rises when it's baking?

First, you didn't ask.

Secondly, I find it

I'll tell her to forget everything she learned today, then.

How'd it get to be my recipe? Just cuz I own the cookbook?

I agree that the experiment is

Yep, you got me there. Spending my entire Sunday in the kitchen helping my kid bake bread is a classic example of hands-off parenting. Especially considering the amount of discussion we had about things AS THEY WERE HAPPENING, the way real valid learning occurs.

I gave her a stack of cookbooks, and she decided which recipe looked like a good one to try. I believe most people would consider that finding the recipe herself, of do you disagree with that too?

I'll be sure to tell her that. She was quite interested to find out that the powder-only loaf did not prown well, and was curious as to why thatwas. She listed that as one thing for further research. Silly child, she should have known all that before she did this. It's common knowldge for most 9 year olds.

I'll make sure she erases the conclusions she came to, then.

So I probably should have squelched her right away when she came up with her own idea for the project, and made her feel stupid, rather than praising her for thinking up something that was in line with her interests. That would make me a much better mother.

One thing she may want to do, if you have enough ingredients that is, is to make more than one batch of each type of bread. That way if one loaf doesn't come out as expected you can see if the results are repeated in the second loaf.

Yup, that's the 'repeated trials' part of the experiment.

So far, she's been having fun, and really interested in her results!

Without knowing what's in the recipe you can't say that the batch with just baking soda will come out flat. There may be an acidic ingredient in the recipe, such as brown sugar.

Actually, the acidic ingredient was the buttermilk. Another independent variable we could have tried was to keep the soda-powder the same, and vary the liquid (milk, water, buttermilk, apple juice) and tested the response to different acidity, but that's a little over her head at her current level of knowledge.

The funny thing is, the all-baking-soda was actually the best loaf. highest rise, fluffiest texture, nice and moist, good crumb, nicely browned. We liked it just as much as the original recipe!!

That's because a given amount of baking soda when combined with an appropriate acid will give off more carbon dioxide gas than an equal amount of baking powder mixed with ordinary liquid.

Combining baking soda with baking acid( sudh as cream of tartar) will not release any gas..... Baking powder mixed with an ordinary liquid such as vegetable oil will not release its CO2 as well... You must be specific what liquid.....and also that there is something that will catalyze the release the CO2 from from the baking acid and baking soda

Combining baking soda and baking powder will usually generate more gases per mole but it depends how you use it....You just can't dump the leavening agents in the batter and expect it to do the works...In fact it may not be able to generate the expected volume of gases....It may also lead to the cake to rise and fall so you will end up with an inferior product.

CO2 is not the only agent that enable to dough or cake to rise....in fact its just one factor, The steam generated is another contributor of any porous baked product volume.

Cool.......maybe she can study that in 5th grade =)