Reverse Engineering Supermarket Peanut Butter

Homemade natural peanut butter is shockingly easy to make. Take some roasted peanuts (or roast them yourselves) and blend or food-process them until they transform into a smooth creamy spread. I have been supplying my family with peanut butter using this method for years. Storing the peanut butter in the fridge prevents the dreaded oil-separation that plagues many store-bought versions, and it's easily customized with a bit of sugar and salt to taste.

What if, instead of "natural" peanut butter, you wanted to reproduce supermarket-style peanut butter like Skippy or Jif. In addition to having a nostalgia-inducing taste and texture profile that many prefer, they remain stable at room temperature. Furthermore, many recipes (e.g. for peanut butter cookies) specifically note that using natural peanut butter will fail to yield optimal results, calling instead for the processed brands.

But wait - couldn't you just go to the store and pick up a jar if you needed it for a recipe? I suppose so, but where is the fun in that? Maybe you want a specific amount on demand. Maybe you want to add your own customizations. Maybe you don't want to support Big Peanut Butter. Regardless of the reason, I decided to try my hand at reverse-engineering this engineered peanut butter.

Skippy seems to be the accepted favorite, so I with Skippy's website, brazenly hosted at peanutbutter.com. From some sleuthing (i.e. reading a web page), I discovered the ingredients included only peanuts, sugar, hydrogenated vegetable oil, and salt, all of which are conveniently in my pantry. Knowing the ingredients is not enough to make a recipe - the proportions are key. This is where the Nutrition Facts label is essential. Skippy reports that a 32 g serving contains 3g of added sugar and 150 mg of sodium.

Starting with the salt, a quick glance at Smucker's Creamy Peanut Butter with No Salt Added revealed that the peanuts themselves contain no sodium, so all 150 mg must be added. Table salt is 39.3% sodium, which we can round to 40% for convenience. This means 32 g of Skippy would contain 150/0.4 = 375 mg of salt, or 0.375/32 = 0.0117 or about 1.2% of total weight.

For the sugar, the calculation is similar. Since a 32 g serving has 3 g of added sugar, this corresponds to a sugar content of 3/32 = 0.094 or 9.4%.

The remaining question is the proportion of hydrogenated oils added. The FDA states that peanut butter must contain at least 90% peanuts.. A USDA website notes "small amounts of hydrogenated vegetable oils are added to commercial peanut butters--at 1 to 2 percent of total weight--to prevent the peanut oil from separating out."

This leads us to a conundrum. Sugar and salt already appear to make up 9.4%+1.2%=10.6%, exceeding the 10% of non-peanut content maximum the FDA mandates. Despite this, Skippy can still call their product "peanut butter", so my assumptions and calculations must be wrong. The answer is likely to lie in rounding. According to the FDA website and other sources, sodium values greater than 140 mg are rounded to the nearest 10 mg, so the sodium content of a serving of Skippy could be as low as 145 mg.

For sugar, measurements over 1 gm are rounded to the nearest g, so the sugar content per serving could be as low as 2.5 g.

The amount of salt per serving would then be 145/0.4=363 mg or 0.362/32*100 = 1.1%

For sugar, this would be 2.5/32*100 = 7.8%

Sugar and salt would then make up 1.1+7.8=8.9% of Skippy, leaving 1.1% for something other than peanuts (i.e. hydrogenated oils).

I suspect most people won't be able to detect tiny differences in fat, sugar, and salt content, so I'm going to simplify the formula to:

• 90% peanuts

• 8% sugar

• 1% salt

• 1% hydrogenated oil

A standard jar of Skippy contains 454 g of peanut butter, but reducing this to 400 g makes the math easier (and ensures the contents will easily fit in my jar):

• 360 g peanuts

• 32 g sugar

• 4 g salt

• 4 g hydrogenated oil

Time to put this to the test.

I roasted some shelled peanuts for about 20 minutes and allowed them to cool. A food processor converted these to a smooth, creamy blend.

Next I measured out my additives. The hydrogenated oil was melted Crisco shortening (I happened to use butter flavor, but the plain variety will do). Salt and sugar were combined in a separate bowl. I melted the shortening in the microwave, then added all ingredients to the food processor with the machine running.

After all ingredients were blended, I used a flexible spatula to ensure everything was evenly mixed, then transferred the mix to a pint-sized Ball Mason Jar (a wide-mouth funnel makes this much less messy). The verdict? Perfect smooth peanut butter that didn’t separate and worked great in a cookie recipe where “natural” peanut butter is supposedly suboptimal.