Figuring out the caffeine content in Trader Joe’s cold brew coffee concentrate
The 32 fluid ounce cold brew concentrate at Trader Joe’s contains the equivalent of about 96 ounces of coffee beverages when reconstituted with water or milk according to their website. The bottle says that it makes 12 8-ounce cups of coffee.
The label does not tell you the caffeine content. We can assume that the Trader Joe’s product follow’s FDA guidelines when making their label. Per FDA guidance for industry, “caffeine content varies in different products” but “a typical eight-ounce cup of ground coffee contains approximately 95 milligrams of caffeine”. If there is enough caffeine to make 12 8-ounce cups, then there is 1200 mg of caffeine in the cold brew container. That means, per fluid ounce of concentrate, we have $1200/32$ or 37.5 mg per fluid ounce. What about caffeine per ounce? Ounces are a weight unit and fluid ounces are a volume measurement. We must multiply the fluid ounce value by the density (ounce per fluid ounce) to get the ounce value. The composition of cold brew is typically a 1:4 coffee to water ratio. The density of coffee grounds is about 0.32 g/cubic centimeter which is ~0.33 ounce/fl ounce. In a 1:4 ratio, the density of cold brew is $\frac{1 \cdot 0.33 + 4 \cdot 1}{(4 + 1)} = 0.87$ ounces per fluid ounce. This is lower than the density of water which is ~1 ounce / fl ounce. We will assume a range of density from 0.87 to 1 to be conservative and err on the side of overestimating the caffeine content. So, there is possibly somewhere from $37.5 \cdot 0.87 = 32$ to 37.5 mg of caffeine per ounce.
Trader Joe’s customer support states that the product contains “50 milligrams of caffeine per one ounce poured”, about ~45% higher than our math suggested. They (Trader Joe’s and the supplier) are defining the caffeine content in a standard 8-ounce cup to be higher than the FDA guidance. There is actually about 43.5-50 mg of coffee per fluid ounce (depending on the density estimate being somewhere between 0.87 - 1). Let’s assume 50 mg of coffee to err on the side of overestimating caffeine content. 100 mg of caffeine is 2 fluid ounces or roughly 60 ml.
#WHy is it good? My theory - coffee is a natural appetite suppressant (but caffeine is not) and we know that mild calorie restriction leads to healthier and longer lives
#How much is good to drink #Problems with teeth https://markhamdentalsmiles.com/is-coffee-bad-for-your-teeth%EF%BF%BC/#:~:text=For%20example%2C%20adding%20lots%20of,it%20can%20lead%20to%20cavities.