To find the total amount of vinegar used in 94 batches, we need to multiply the amount of vinegar used in each batch by the number of batches.
Given that each batch uses \( \frac{1}{2} \) gallon of vinegar:
\[ \text{Total vinegar} = \text{amount per batch} \times \text{number of batches} \]
Substituting the values:
\[ \text{Total vinegar} = \frac{1}{2} \times 94 \]
To perform the multiplication:
\[ \frac{1}{2} \times 94 = \frac{94}{2} \]
Now, we simplify \( \frac{94}{2} \):
\[ \frac{94}{2} = 47 \]
Thus, the total amount of vinegar used in 94 batches is
\[ \boxed{47} \text{ gallons.} \]