I finally decided to give tallow a try when I found this shortening at a regional Walmart. At first I thought it was the one with palm, but when I got home I realized it is tallow, lard and soybean oil. Soybean oil always makes me a little nervous, which is what brought me to this thread.
After reading
@earlene ‘s post above, it occurred to me that additional information given on the can for this product should be useful for approximating the composition.
The can lists the distribution of fats in an 11 g serving as follows:
saturated = 4.5 g
trans = 0.5 g
monounsaturated = 4 g
polyunsaturated = 1 g
This adds up to 10 g of fat, not 11. I don’t know how to account for that missing gram of fat, so I just ignored it and set my total fat to 10 g for further calculation. Thus, the mixture of tallow, lard and soybean oil should have 45% saturated, 5% trans, 40% monounsaturated and 10% polyunsaturated. The trans fat could be anything, but with hydrogenated tallow in the ingredient list, I assumed the trans fat is of a saturated fat. If saturated = Lauric + myristic + stearic + palmitic + trans; monounsaturated = oleic; and polyunsaturated = linoleic + linolenic, a close fit using the SMF calculator is as follows:
tallow = 51%
lard = 39%
soybean oil = 10%
which yields the following FA profile:
saturated = 47%
monounsaturated = 39%
polyunsaturated = 10%
This accounts for only 96% of the fatty acids. As I understand it, this is because the calculators don’t include every type of FA that can be present in the oils. Close enough, I think.
A composition of tallow (40%), lard (39%), hydrogenated tallow (11%) and soybean oil (10%) would be consistent with the order of ingredients listed on the can. The sap for the mixture I estimated is 0.141 according to the SMF calculator, which returns 141.35 g of lye needed for 1000 g of oils. Although my percentages vary a bit from those estimated by Earlene, in the end, the sap estimate is the same
. And happily, the polyunsaturated (linoleic +linolenic) percentage is in a range I can deal with.
ETA: according to the SMF calculator, the Walmart tallow/palm blend has 54% saturated, 37% monounsaturated and 7% polyunsaturated fats and a NaOH SAP of .141. Until the calculator is updated, I will probably use that blend as a proxy for the tallow/lard blend. The SAP should be fine, but I anticipate that the calculated recipe will be off a bit on the hardness and longevity. If my calculations are close, the soap will be slightly softer and less long lasting due mostly to lower percentages of palmitic FA in the tallow/lard blend compared with the tallow/palm blend.