Yeast cells typically stain pink or red in a Gram stain. This is because they have a thin peptidoglycan layer in their cell wall, making them Gram-negative.

However, it's important to note that:

* Some yeasts can stain Gram-positive due to variations in their cell wall structure.

* The Gram stain result can be influenced by factors like age and growth conditions of the yeast culture.

Therefore, while yeast is generally considered Gram-negative, it's not a foolproof method for identification, and further tests may be necessary for conclusive identification.