Having a friend who raises ducks means that we have ample opportunities to test duck eggs in recipes. How does using yolkier eggs alter baked goods like cake and cookies?

Initial observation: As previously established, duck eggs have larger yolks (and thus greater fat content) than chicken eggs.

Question: How does the use of duck eggs in baked goods affect the end results?

Expectation: It is commonly touted that duck eggs produce baked goods that are moister, and richer, than when made with standard chicken eggs. Given previous results quantifying the volume and yolk size of chicken vs. duck eggs, that seems like a reasonable claim.

Equipment & Materials:

• boxed cake mix/recipe + ingredients
• eggs (chicken & duck)
• scale (American Weigh Kitchen Scale 2000 gram x 0.1g)
• hand mixer (in the name of science, a mixer was used to ensure uniformity: KitchenAid 5-Speed Ultra Power Hand Mixer, though I normally prefer a wooden spoon)
• optional: instant read thermometer (Thermapen)
• optional (?): frosting! Here at the primary testing facility we are fond of the Dream Whip frosting “recipe” … it is not overly sweet and the flavor can be varied by simply picking any of the available instant puddings at your local food purveyor.

Cake Procedure:

1. mass the boxed cake mix and divide into two bowls (Note: the box utilized contained 434.5 g of mix, which was different than the 432g stated on the box)
2. the box called for 3 eggs; an “ideal egg” is 55g, so the recipe needed 165g of egg total, or 82.5g of egg for each half batch/layer
3. crack open and lightly beat 2 chicken eggs
4. mass out an amount close to 82.5g
5. add massed egg to one half of the cake mix
6. repeat steps 3-5 with 1 or 2 duck eggs plus the other half of the cake mix
7. beat each half-batch with mixer for 30 seconds at low speed, and then 30 seconds at medium
8. pour batter into two prepared cake rounds, bake as directed
9. mark each batch of batter with a drop of food coloring for identification
10. to account for oven unevenness (thermal or old-house flooring issues) pans were rotated & swapped places at about 15 minutes
11. finish baking, remove from oven, cool as directed, construct a cake, consume & enjoy!

Cookie Procedure

1. divide the target recipe in half, measure ingredients into two separate bowls (this helps ensure each half-batch gets the proper amounts of salt, leavening, etc…)
2. if an “ideal egg” is 55g, multiply the half-batch egg requirements by 55g to determine the amount of egg needed
3. crack open and lightly beat a chicken egg
4. mass out the amount determined in step 2
5. add egg to one half-batch and mix as directed
6. repeat steps 3-5 with duck egg(s) for the other half-batch
7. finish constructing cookies according to recipe
8. bake as instructed, remove from oven, cool, imitate cookie monster & enjoy (om nom nom!).

Cake Data:

Both of the cake layers were nearly the same temperature when removed from the oven (206°F for the chicken-egg layer, 204°F for the duck-egg). The height of the finished cakes were slightly different, with the duck egg version obtaining slightly higher maximum elevation (1.31″ vs. 1.25″). For taste testing, Brownie Master P and Co-blogger/Science conspirator F were presented with the finished & dressed cake, and were not informed about the layer identities. Both “blind” testers , preferred what was the duck-egg layer. It was determined that there were no obvious textural difference, but the there was a slight flavor difference, with the duck egg layer being considered more flavorful.

Cake where the upper layer was made with duck eggs and the lower layer with chicken eggs.

Surprise Results:

As the testing facility hosts a low permanent population (most of whom are obligate carnivores), the cake constructed for this experiment lingered for a while in the fridge. It was noticed that after a week or so, the duck-egg layer was noticeably more moist than the Chicken-egg layer. This may be a result of the upper cake layer having a larger frosted surface area than the bottom layer (I don’t frost the bottoms of cakes, not even for science), but the keeping characteristics of duck vs chicken egg goods should be tested further.

Conclusion:

The preferences were subtle, but duck eggs had a slight edge over the chicken eggs in both the cake and cookie tests. The cake constructed with the duck eggs were slightly loftier, and the duck egg cookies were considered chewier, fluffier, and lighter in color (and overall “prettier”).

Future Questions:

Is the moisture difference after 1 week due to the type of eggs used, or the frosted surface area? What happens if eggs are not weighed out for the recipe, and an integer number of duck eggs are swapped equally for the number of requested chicken eggs? Similarly, what if the amount of chicken egg was increased to match the internal mass of duck eggs that might be used (i.e. are commonly stated preferences for duck eggs mainly because they are larger than standard chicken eggs?)

Doing science to baked goods is a great reason to bake! In case you are interested, T-Shirt can be obtained here and is from this web comic.