# Where are acids and bases found in nature?

Most of the things that we eat that taste good, are slightly acidic. For instance, wine, cheese, butter, lemon juice, vinegar, egg yolk, are all slightly acidic.....$p H = 5 - 7$. The most basic thing that we eat is quite probably egg white, $p H \cong 8.9 - 9.1$. (Note that interestingly, when an hen's egg is freshly laid it has a $p H$ of $7.8 - 8.0$; I am told that on storage it loses (the acidic oxide) $C {O}_{2}$ and $p H$ rises.....the shell must be permeable to $C {O}_{2} \left(g\right)$) The soapiness and bitterness of egg-white is quite characteristic of a base.