Fresh yeast, sometimes called cake yeast or compressed yeast, is a block of fresh yeast cells that contains about 70% moisture and is commonly used by baking professionals. It's pale beige in colour, with a texture similar to a soft pencil eraser, and has a stronger yeast smell than dry yeast.

Fresh yeast is soft and moist. Dry yeast (by contrast) is fresh yeast that has been pressed and dried until the moisture content makes the yeast dormant (until mixed with warm water). Dry yeast has a much longer shelf life than fresh yeast and does not need to be refrigerated unless opened.

For dry active yeast, you generally need to use half the quantity of fresh yeast stated in the recipe and for instant yeast you need to use 1/4 of the quantity of fresh yeast. So if the recipe has 30g (1 ounce) fresh yeast then you can use 15g (1/2 ounce) active dry yeast or 7g (1/4 ounce) instant yeast instead.