My Amazing Baking Spreadsheet – The Enginerd in Me Comes Out

Now, if you know me, or have read my About Me page, you know I am an engineer.  Engineers like spreadsheets. I LOVE spreadsheets!  Spreadsheets are my best friend.  Excel and I go way back to freshman year of college.  And since then, our relationship has blossomed and flourished; and, while I sometimes want to punch my spreadsheets at work in the face, I have found spreadsheets extremely useful outside of work.  I have used them for a wide range of things, from budgets, to Broadway show decisions, to storing important information, to baking.  That being said, I made an elaborate spreadsheet to not only price out the exact cost of making this beautiful wedding cake (ingredients and supplies included), but also to estimate the number of batches I will need of icing and batter.  I felt this was important so I could be prepared with amount of ingredients I need to purchase, and it is also good to know how much I am spending (my baking hobby can get pretty costly pretty quickly).  In this post, I just go over the estimation of batter and icing.  I do not go into the cost…That can be another post (maybe after the wedding…IT’S CRUNCH TIME!).

Now, my (extremely correct by volume) calculations estimated I would need 2 batches of my cake recipe to make one 14″ layer and one 12″ layer.

firstcalc2

*Height is the batter height, assuming cake pan is filled 2/3 of the way (this is standard).
**Volume is calculated, not actual.
***Icing needed is the amount to cover cake in icing.  This does not include decorating the cake.  Another batch is suggested to decorate cake (amount varies depending on amount of decoration).  1 batch = ~3 cups
NOTE:  Wilton estimation is the amount Wilton says you need.  Their estimates are low.

This was NOT accurate!  When it came down to it, I needed to make an additional 1/2 batch to complete the two layers – 2.5 batches total (and a tiny bit more wouldn’t have hurt either).  Devastated (obviously, sigh) by the inaccuracy of my beautiful spreadsheet, I went back to investigate the cause of the offset.  I discovered the most likely culprit to be that my recipe says it is for two 9″ x 2″ layer round cakes, but I have never tested this.  So all my calculations were based on this assumed volume, while the actual volume is probably a little less. (I used 9″ x 1-1/3″ volume of batter, since it is standard to fill your cake pan 2/3 full with batter.)  So, using my engineering skills, I took the calculated amount needed and the actual amount I used, and made a quick correlation (I used 2.6 batches as the amount needed for one 12″ and one 14″ layer, since I could have used a little more batter for that cake).  My correlation came out to about 1.24 x my original estimated amount of batter.

correlation

This correlation I believe to be pretty darn accurate.  It says that a 6″ x 4″ layer cake requires 0.55 of a batch of my recipe, which is just about what I found.  I made 1/2 a batch, and could have used a little more, because one of the layers was slightly thinner than I would have liked.  It estimates my 8″ cake to be 0.98 batches, which may be slightly high because I always have just a little too much batter to put in the two pans.  But I would much rather have a little high estimate and make too much batter, than not enough and have to go back and make more.

correlation calc

Sidenote:  I posted on Facebook that my beautiful spreadsheet let me down by telling me I needed less batter than I actually required, and my very sassy chemical engineering friend responded, “Remember ingredients in baking don’t scale linearly.  Did you calculate the dimensionless numbers? …Didn’t Dr. Ferri teach you anything?”  He is a clown.  Whatever!  But since linearly is what is easiest (hehe), and I would not even know where to start scaling nonlinearly, that is what I stuck with.  As for dimensionless numbers – baking is just as much an art as it is a science, so I went with the “that seems like it will be enough” method.  If you do not know what “scaling linearly” and “dimensionless numbers” means, this post probably isn’t for you.  :/  Sorry, but baking is supposed to be fun, and I don’t want to bog it down TOO much with calculations and formulas and mathematical explanations.  If you reeeaally want to know more, leave a comment and I’ll get back to you…or there is always Google.  🙂

I also estimated the amount of butterceam I will need, though I did not go super high-tech and go into surface area, icing thickness, volume – which I could have done.  This seemed obscene though, and unnecessary, and even I have my limits with what I will do with a spreadsheet.  Plus, seeing how my last calculation panned out (haha, no pun intended), it probably wouldn’t have been that accurate anyway.  So, I just guesstimated based on the amount of buttercream I used for the different sized cakes I have made so far.

icingcalc

As a result, I will make 7 batches of batter (but have ingredients for another batch on stand-by), and 8 batches of buttercream (and also have ingredients for 2 more batches on standby).

total

I will do this over a three-day period (Monday-Wednesday next week), and pack up and drive up to Connecticut Thursday evening.  Friday, I will assemble the cake!  I think I will make at least some of the fillings this weekend, since they are easy and will last fine for a week.  I will also make the sugar sunflowers tonight!  So wish me luck!

Moral of this story:  Always be prepared!  (And spreadsheets are not perfect unless you are.)

Disclaimer:  If I totally lost or bored you in this post, I am sorry.  I let the enginerd inside get the best of me.  I’d promise I won’t do it again, but I fear that would be a straight-up lie.  I’m an engineer, and I can’t help it sometimes.  :/  Oops!

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