The consensus seems to be that, unless you have something to bake right away in which you could use the buttercream, you should freeze it. That's right: don't toss that buttercream! It will remain good in the refrigerator for 4-5 days. Alternatively, put it in an airtight container and freeze it up to 3 months. When ready to use again, take out of the freezer and place in the refrigerator overnight to thaw.
The pH scale runs from 0 to 14, with each number assigned a different color. At the bottom of the scale sits red, which represents the most acidic, and a dark blue at its opposite end represents 14 and alkalinity. In the middle zone, the pH scale becomes neutral. Milk has a pH of 6 and a neutral off-white color.
The pH scale measures how acidic or basic a substance is. The pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic. The pH scale is logarithmic and as a result, each whole pH value below 7 is ten times more acidic than the next higher value. For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6. The same holds true for pH values above 7, each of which is ten times more alkaline (another way to say basic) than the next lower whole value.