Calculating the True Price of Food: Starches Edition

Mashed potatoes, made from 100 grams
of potato and dehydrated potato

You're in the store and you see barley, rice, and pasta all with a relatively decent price. You start comparing prices to see which gets you the largest quantity for the least price, so you take out your calculator and start doing the math. But wait- you're missing an important part of the picture!
If you take one pound of rice, one pound of noodles, and one pound of barley, do you end up with only one pound of each type of the finished product? If not, do you end up with equal amounts of the finished product? How do you even know?

I had fun last night, performing a kitchen experiment, one of a few in a series which will follow. I bought a whole bunch of different starches, cooked 100 grams of each of them, and saw how many grams of end product I got for each food. With this, I've devised a table for you to figure out how much you're paying for your finished product, so you can do a more accurate price comparison in the store, to see which item is truly most worth your while to buy (nutrition factors aside).

The True Price of Starches

The contestants:
White flour macaroni
White rice
Brown rice
Pearl barley
White flour- made in three different ways- pancakes, tortillas, and pitas.
Sweet potatoes- made in two different ways- boiled, and baked.
Potatoes- made in four ways- boiled, boiled and mashed, baked, and french fried.
Instant mashed potatoes

The results:

Food	Cooking method	Start weight	End weight	Weight change	Figuring out real cost per weight	Example of true cost
White Rice	Boiling w/ 2:1 ratio w/ water	100	240	240.00%	Cost per dry weight divided by 2.4	Raw white rice at $1/lb really costs $0.42/lb of cooked rice.
Brown Rice	Boiling w/ 2:1 ratio w/ water	100	200	200.00%	Cost per dry weight divided by 2	Raw brown rice at $1/lb really costs $0.50/lb of cooked rice.
White Macaroni	Boiled in water, strained	100	250	250.00%	Cost per dry weightdivided by 2.5	Raw macaroni at $1/lb really costs $0.40/lb of cooked macaroni
Pearl Barley	Boiled in water (until not chewy), strained	100	297	297.00%	Cost per dry weight divided by 2.97	Raw barley at $1/lb really costs $0.34/lb of cooked barley
White Flour Tortillas	Mixed w/ water, dry fried	100	130	130.00%	Cost per dry weight divided by 1.3	White flour at $1/lb really costs $0.77/lb of tortillas
White Flour Pancakes	Mixed w/ water, fried in sunflour oil	100	175	175.00%	Cost per weight divided by 1.75	White flour at $1/lb really costs $0.57/lb of pancakes
White Flour Pitas	Mixed w. water and 1 tsp yeast, dry fried	100	146	146.00%	Cost per weight divided by 1.46	White flour at $1/lb really costs $0.68/lb of pita
Boiled Potatoes	Boiled in water, strained	100	98	98.00%	Cost per weight divided by .98	Potatoes at $1/lb really costs $1.02/lb of boiled potato
Baked Potatoes	Baked in oven until soft	100	75	75.00%	Cost per weight divided by .75	Potatoes at $1/lb really costs $1.33/lb of baked potatoes
French Fried Potatoes	Fried in sunflower oil until golden	100	49	49.00%	Cost per weight divided by .49	Potatoes at $1/lb really costs $2.04/lb of French Fries
Boiled Potatoes Mashed	Boiled, then mashed, water added until creamy	100	129	129.00%	Cost per weight divided by 1.29	Potatoes at $1/lb really costs $0.76/lb of mashed potatoes
Boiled Sweet Potato	Boiled in water, strained	100	100	100.00%	Cost per weight divided by 1	Sweet potatoes at $1/lb really costs $1/lb of boiled sweet potato
Baked Sweet Potato	Baked until soft	100	60	60.00%	Cost per weight divided by .6	Sweet potatoes at $1/lb really costs $1.67/lb of baked sweet potato
Instant Mashed Potatoes	Water added until creamy	100	570	570.00%	Cost per weight divided by 5.7	Instant mashed potatoes at $1/lb really costs $0.18/lb of ready mashed potatoes

All made from 100 grams of flour

Notes on the chart:

Water prices were not included, nor were oil prices for pancakes or French fries, which would up their price. 

For the pita, 1 teaspoon of bulk yeast was added, which cost less than a penny, so it wasn't added to the price.

No other things were added to the foods, no salt, no sugar, no spices, no eggs, no butter, no oil unless noted.

All the foods were prepared how they'd usually be prepared- the noodles were regular, not mushy. Rice was prepared with a 2:1 ratio of water to rice, as it usually is. The barley was cooked until it was not chewy, but not mushy. The potatoes were boiled until soft, but not falling apart. The baked potatoes and sweet potatoes were baked until they were soft, but not burnt.

Applying the results to our life:
If everything cost the same amount per pound, it would be easy to see that the cheapest choice of starch would be mashed potatoes, then barley, followed by macaroni and then white rice and brown rice. However, each product in the store has a different price.
Where I live, stores sell 500 gram bags of pasta for $0.82. First, you need to figure out the cost per pound or kilogram. This pasta costs $0.74 per pound.
Rice, on the other hand, comes in 1 kilogram bags for $1.37, which is $0.62 per pound.
Pearl barley costs $1.68 for a 500 gram bag, which is $1.53 per pound.
Brown rice costs $2.88 per kilogram, or $1.31 per pound.
White flour costs $0.69 per kilogram, or $0.31 per pound.

Just from the initial price, you'd assume that white flour is the cheapest starch, followed by white rice, then pasta, then brown rice, then barley.
But before we can be sure if that really is the order of cheapest to most expensive, we have to apply the numbers in the chart above.

To figure out the true price of pasta, you need to divide $0.74 by 2.5. With this conversion, you'd discover that the true price of the pasta is $0.30 per pound.
White rice you'd divide by 2.4 and get a total of $0.26 per pound.
Pearl barley would be divided by 2.97 and get $0.52 per pound.
Brown rice would be divided by 2 and get $0.65 per pound.
White flour, depending on what you're making, would either be $0.24 per pound (tortillas), $0.18 per pound (pancakes), or $0.21 (pitas).

It works out that the cheapest foods to make, in order, are pancakes, pitas, tortillas, white rice, pasta, pearl barley, then brown rice. While this is similar to the order if you hadn't done the calculations, you'd discover that brown rice is more expensive than pearl barley, even though, when dry, the barley looks more expensive.
You also discover that the price of white flour and rice are not that different, so if rice is on sale for $0.50 a pound, and the price of white flour goes up to $0.38 per pound, the real rice price would be $0.25 a pound, making it cheaper than the flour's $0.29 cents a pound tortillas, but still more expensive than the $0.22 cents a pound pancakes and just a tad cheaper than the $0.26 a pound pitas.

Mashed potatoes price comparisons would be as follows:
Assume that you bought the instant mashed potatoes, 400 grams for $2.65 at the local grocery store, or $3.01 per pound. Bought potatoes for $1.23 per kilogram, would be $0.55 per pound..
However, the real price of the mashed potatoes from fresh potatoes would be $0.43 per pound, and the instant mashed potatoes would be $0.53 per pound.
In such a case, the fresh mashed potatoes would be cheaper by a little.
However, I'm buying instant mashed potatoes in bulk for $1.42. The mashed potatoes made from the bulk bought stuff would be only $0.24 per pound, which is cheaper than the mashed potatoes made from the fresh stuff, as well as being cheaper than white rice, pasta, brown rice, and barley.

Of course, these numbers don't necessarily apply to you, but I hope that by showing you this process, you'll be able to figure out which starches are truly cheapest per pound where you live.

Water

Water really makes the biggest difference in determining the final price of a food. Foods like barley and instant mashed potatoes that absorbed the most water during preparation end up being the most cost efficient. On the other end of the scale, foods like French fries and baked sweet potatoes that lose much of their water while cooking end up being the least cost efficient.

It may seem silly to factor water weight into figuring out the true cost of an item, but the fact of the matter is that water really makes our portions larger, which tricks us into thinking we're getting more food, which makes us end up being satisfied with less food. Case in point- while you can probably eat a whole bag of dehydrated apple chips, you probably won't find yourself eating more than one or two apples in one sitting.
Water both fools our minds and actually fills us up, so yes, water weight definitely is included when figuring out the true cost of a food.

Coming soon in this series:
Calculating the true price of beans
Calculating  the true price of proteins
Calculating the true price of cereals

Have you ever figured out the prices of different starches based on the finished product? Do you think calculating costs this way is accurate or not?
Would you use this chart to help you determine which starches are cheapest to buy where you live, or is it too complicated?