There is a misunderstanding in the question. "Quarter ounce" already refers to a specific amount.

Here's the breakdown:

* Ounce (oz): A unit of weight.

* Quarter ounce (1/4 oz): Exactly one-quarter of an ounce.

Therefore, there are no additional ounces in a quarter ounce of yeast. It's simply a fraction of a full ounce.