Why Your Pre-Shredded Cheese Won't Melt

Pre-shredded cheese is a major boon when you don't feel like whipping out a hunk of cheese — just pour it straight from the bag and go. However, this convenient ingredient is notorious for one trait that might make a huge difference to your dish: It doesn't melt, at least not to the uniform ooey-gooey consistency of standard block melting cheeses. This may not be such a deal-breaker if you're topping a baked potato or mixing some into a green salad, but using pre-shredded cheese is one of the most common mistakes when making cheese sauce, fondue, pizza, or other dishes that require meltiness. Instead of yielding photogenic cheese pulls, the dairy product ends up still separated and only partially melted — an unappetizing sight with a lumpy mouthfeel. 

The culprits behind pre-shredded cheese's inability to melt are the very additives that keep it looking nice and separated in its packaging: cellulose or anti-caking blends that contain one or more starches. (Block cheese doesn't contain anti-caking agents, which is why it melts so beautifully.) Any store-bought pre-grated cheese will contain some mixture of these agents; you can't escape them. So as time-consuming as it may be — particularly if your recipe calls for a lot of cheesy goodness — you might be better off buying a block of cheese and shredding it yourself.

There are several different anti-caking agents you might find on your bag of pre-shredded cheese, and although these additives prevent the cheese from melting, they do serve a vital purpose in terms of shelf stability. Without them, the cheese would no longer be shredded by the time you laid eyes on it at the store; it would be a big clump that you'd end up having to grate anyway. 

Cellulose is one common coating used to keep pre-shredded cheese shredded. This carbohydrate is sourced from cotton and trees (it's basically wood pulp) and then processed into a fine powder with the aid of salt and acetic acid. While it may sound a little odd to have wood pulp in your cheese, cellulose is actually a safe and common component of many food products, including some salad dressings and peanut butters, where it helps to maintain texture and keep the components properly mixed. 

Cornstarch and potato starch are also readily found in pre-shredded cheese. (Yes, preventing clumpy cheese is another cool thing you never knew cornstarch could do.) Made by extracting the starchy portions of these high-carbohydrate foods, these starches draw in excess moisture, preventing stickiness. However, you'll end up with unmelted cheese whether your bag contains cellulose, cornstarch, or potato starch. So, if it's sumptuously stretchy meltability you're looking for, get your grater out and save the pre-shredded stuff for quick snacks, baked potatoes, and other dishes where "not melted perfectly" is perfectly adequate.