A 1980s-era commercial for Philadelphia Cream Cheese, rather disingenuously, stated that their product, ounce for ounce, had half the calories of butter. Following this proclamation, and in tones generally reserved for a very different sort of act, the announcer throatily exhorted that we “spread it on” as a butter knife massaged a layer of luxurious, alabaster cheese across a piece of bread to a depth that could have reasonably hidden Rambo from the Vietnamese army. The fact that one doesn’t generally apply butter in amounts sufficient to cement together a bagel, two slices of tomato, some capers and a generous portion of lox was not touched upon. When this was suggested to me some time later by my parents, I was broken-hearted. How could something as purely good as cream cheese be party to something so sorted?

Now, decades later, I am happy to say that I have returned to the field of honor to defend a dairy product who has been sorely misused by those to whom had been entrusted the duty to protect her. I present the cheese that should have been: Vitamin C and Calcium Fortified Cream Cheese – C4.

There are a number of ways of adding calcium to your diet. The easiest, of course, is to drink more milk and eat more leafy green vegetables. However, this Instructable is not about easy - it is about honor. We will be adding the calcium and vitamin C to our CC using (mostly) homemade calcium ascorbate, also known as “buffered vitamin C.” What’s more, the calcium portion of this will come from egg shells, an ordinarily ignored part of the groceries we purchase. Farmers add calcium to the diets of chickens to support the amount needed to create the shells for the eggs the hens lay. The cost of the calcium is passed on to the consumer who buys the eggs, a consumer who, 99 times out of a hundred, throws away this calcium after eating the eggs.

Egg shells are over 90% calcium carbonate (CaCO₃), a very common form of calcium present in animals and plants. While you could eat CaCO₃ and gain some benefit from it, it’s gritty and not terribly bio-available, meaning a significant potion of the calcium will simply "pass through" without being used by your body. A more efficient means of getting this calcium is to mix the carbonate with citric acid from … well, citrus fruit. This is much more bio-available and tastier, but it still, in my opinion, falls short. After all, citric acid, though nice and tangy, doesn’t have much going for it, nutritionally. However, if you mix your eggshells with ascorbic acid, well not only is the calcium bio-available, but it comes wrapped in healthy vitamin C! Mix it in cream cheese, add some additional flavors, and it’s not only great tasting, it's great for you, so … spread it on!

For this instructable you will need the following:

Ingredients:

Cream cheese (organic, if possible)
Egg shells (from organic eggs - seriously. Factory farming renders the eggshells of eggs unfit for human consumption)
Ascorbic acid (NOT buffered vitamin C – I got mine from a homebrew shop)
Lemon juice
Dill (dried)
Garlic powder (yeah, I know, but it’s easier than fresh for this recipe)
Salt
Pepper
Distilled or purified water

Tools:

Scale capable of working in .5-gram increments (optional, but very helpful)
Measuring spoons
Children’s medicine dropper (with children’s medicine, or free from a pharmacy - just ask)
Funnel (optional)
Coffee filter or paper toweling
Means of blending ingredients (i.e. food processor, whisk or fork)

The total cost of this project is quite low. The ascorbic acid is arguably the only thing the average person might not have, and it costs a few of dollars, tops.

WARNING:

Although the levels of vitamin C and calcium used in this recipe are not dangerous, keep the unused portion of the calcium ascorbate out of reach of children, and keep it well-labeled. Drinking the entire mixture straight would upset your stomach and, if you're taking calcium supplements at the same time, could result in hypercalcaemia, which would be unpleasant. If you have impaired kidney function, talk to your doctor before adding calcium to your diet.

UPDATE: I've done some further reading on salmonella, and I've got some additional advice. When prepping your eggshells, I now strongly recommend that you heat them prior to grinding. The USDA recommends that eggs (and presumably their shells) be heated to at least 160 degrees Fahrenheit (internal temperature). Annecdotal evidence supports the idea that salmonella should be less prevalent on organic or free range eggs, but annecdotal evidence also supports the idea of putting raw egg and flour on third-degree burns, which is just nuts. The Wikipedia article states that salmonella is killed after being heated to 167 Fahrenheit for 10 minutes, however the links used to support this claim make no reference to this temperature or duration. For this reason, I tend to favor the 200 degrees Fahrenheit for at least 30 minutes suggestion I made in this instructable. This will certainly destroy some helpful amino acids, but that's not why we're using eggshells in this Instructable.

I would also suggest that this instructable only be used in food for adults for both of the caveats mentioned above: hypercalcaemia and salmonella. Children are more susceptible to both of these conditions - especially salmonella. I can't imagine there are many people giving cream cheese to infants, but obviously don't give them our modified CC either.

I don't mean to sound alarmist here. We've all eaten fragments of eggshell or undercooked egg before, and chances are we've had no ill-effect. The above information is just here to help you make an informed decision about this project, one that I hope will include further research on your own part.

Step 1: Prepare the Eggshells

It takes about one or two egg shells to make this recipe, but I tend to do more than that at a time in the interest of efficiency. First, wash your eggshells, to remove any raw egg. If you have hard-boiled your eggs, then this step is unnecessary. Allow the clean eggshells to dry. Some people advocate drying your eggshells in the oven at 200 degrees Fahrenheit for half an hour to kill any bacteria (see my update on page 1 regarding salmonella). This will probably also destroy any amino acids present in the eggshell, but to my mind, that’s not a deal breaker. After drying (or heating) your eggshells, you will need to grind them. You can use a food processor or even a rolling pin for this, but the best tool (I’ve found) is a clean (!) coffee grinder.

The picture here shows before and after, i.e. unground and ground eggshells.

Step 2: Chemistry!

Once the shells are pulverized, we will need to work out the amount needed for the chemical reaction involved.

For those interested, here’s what going on chemically (for those less interested, skip to "CHEMISTRY BIT ENDS HERE" below):

CHEMISTRY BIT STARTS HERE

Calcium carbonate combines with ascorbic acid in a stoichiometric ratio of 1:2. Here’s the formula:

CaCO₃ (calcium carbonate) + 2C₆H₈O₆(ascorbic acid) ==> C₁₂H₁₄CaO₁₂ (calcium ascorbate) + CO₂ (carbon dioxide) + H₂O (water!)

This means that for every calcium carbonate molecule, you will need two ascorbic acid molecules. Ascorbic acid is also the heavier of the two, which means you will need quite a bit more (by weight) of it than calcium carbonate if you want this reaction to proceed efficiently.

The molar mass of CaCO3 is roughly 100 g/mol, while the molar mass of ascorbic acid is 176 g/mol, but we need twice as much (see equation above), or 352.24 g of ascrorbic acid per 100 g of CaCO3. This means that, by weight, we will be using 28% as much calcium carbonate as ascorbic acid.

CHEMISTRY BIT ENDS HERE

To simply the math, we will start with 10 grams of ascorbic acid and 2.8 grams of CaCO3. You can either weigh this out on a scale, or approximate these amounts using your measuring spoons.

5 grams of ascorbate acid should be roughly one teaspoon, so use two teaspoons for the recipe.
2.5 grams of CaCO3 (eggshells) is about a half teaspoon. Add a bit more (maybe use a rounded teaspoonful, rather than a level teaspoonful) to get it close to the 2.8 grams.

If you have jury-rigged a balance scale, one U.S. nickel weighs 5 grams and one U.S. penny weighs 2.5 grams; therefore you are adding two nickels' weight of ascorbic acid and one penny + .3 grams of CaCO3. I would just add a bit more to approximate the extra .3 grams. We will be filtering this later, and any excess, unreacted CaCO3 will remain in the filter.

Step 3: Making the Calcium Ascorbate

Now, if you’re a baker, you will be thinking that you should mix all the dry ingredients, then fold in the wet. That was my first instinct too, even though a little voice in the back of my head was saying “do what you oughta: add acid to water.” You can see from the first picture the result (bad is on the left, good is on the right). The calcium carbonate dissolved poorly and the whole thing is rather unpleasant. If your recipe calls for gritty, bitter meringue, then this may be the way to go. For our purposes though, it’s much nicer to mix the ascorbic acid in the water, then slowly add calcium carbonate while stirring.

Here’s how: in a small bowl, add 25 ml of near-boiling water and then add 10 grams of ascorbic acid. This will take a little while to dissolve. Stir carefully, grinding the powder with the back of your spoon to facilitate mixing. Now add the eggshell powder to the acid. Add a little at a time, stirring constantly. It will foam as the CO₂ is liberated and the calcium combines with the ascorbic acid. It will not smell particularly nice. Once all of the eggshell has been added set the mixture aside for about an hour or two, until the foam subsides and the eggshells are almost entirely dissolved. You will want to filter this solution now, to remove any stubborn pieces of shell or other debris from your solution. When filtered, it will look cloudy, but there will be no grit or other solids.

As this reaction is not perfect, and not all of the CaCO₃ reacts with the acid, the resulting solution will not be neutralized. You can expect it to be still a bit acidic. You can neutralize this a bit more by adding baking soda – not much! This creates sodium ascorbate, another buffered vitamin C, with its own benefits. Alternatively, if you have magnesium carbonate, you can add some of this increase pH.

Do NOT add potassium carbonate.

Although potassium is a vital nutrient, larger amounts of it can be quite dangerous. The final chemical in a lethal injection is frequently potassium chloride, which, in a high enough dose, stops the heart from beating. Don’t mess with potassium in your food unless you know what you’re doing.

Now, you have 25 milliliters of buffered vitamin C - AKA calcium ascorbate. Store this in the refrigerator until such time as you need it.

Step 4: Letâs Make the Cheese Spread!

Because your vitamin C mixture is still probably a little acidic (around pH 5 or 6 - see the pH tests in the first picture) and may have a somewhat salty or metallic taste, you will want to go with citrus flavors for your cream cheese. I haven't tried sweet citrus, just savory, but sweet could also work.

Here’s my recipe:

For every 1 Tablespoon of cream cheese add:

1 milliliter of calcium ascorbate
¼ tsp lemon juice
1/16 tsp dill
1/16 tsp garlic powder
salt and pepper to taste

Mix your liquids first (lemon juice and calcium ascorbate), then add them to the cream cheese and mix. This will make the cream cheese softer, and as a result, it will be easier to add the dry ingredients. Once the wet ingredients have been thoroughly mixed, and the cheese mixture has softened, add the dill, garlic, salt and pepper.

In the picture here, I used four tablespoons of cream cheese, so the amounts of the other ingredients are as follows:

1 tsp lemon juice
¼ tsp dill
¼ tsp garlic powder
salt and pepper

If your spread has a more tangy citrus-y taste, try adding a little more salt and garlic. Because of variables like fineness of the grind for your CaCO3, you may have a different level of acid (tanginess) from batch to batch.

Step 5: Additional Notes/nutrition

As much as I love cream cheese, it’s just not the healthiest food on its own. One serving (two tablespoons) has 28 milligrams of calcium and zero vitamin C. An average human requires 400 mg of calcium per day, and can easily use up to 1000. Our C4 supercharged cheese has 117 milligrams of calcium and 748 milligrams of vitamin C per serving! That’s equivalent to what you would get with an Emergen-C packet, and it goes better with lox!

If you want more calcium, and less vitamin C, you can use the calcium citrate method of adding egg shells to lemon juice, as described here. The replace the lemon juice with the citrate mix. I would do 1/4 teaspoon of calcium carbonate tops if you include the calcium citrate recipe used here.

Caveats: some folks mega-dose with vitamin C. Please note that mega-dosing on calcium ascorbate is not advisable. You are getting a significant amount of calcium with every gram of ascorbic acid, and you can get in trouble once you hit levels of greater than 1000 milligrams of calcium per day. If you would like any further information on ascorbates and health, or on calcium in general, check out the following links:

http://lpi.oregonstate.edu/ss01/bioavailability.html
http://www.livestrong.com/article/509693-calcium-ascorbate-vs-ascorbic-acid/
http://ods.od.nih.gov/factsheets/calcium
http://www.sciencelab.com/msds.php?msdsId=9923244