Well. I made mozzarella Saturday. Got just under a pound from a gallon of whole milk. Very mild, as is all new mozzarella made without lipase or some flavoring. I'll let it age for a week, since that's said to deepen the flavor, and next time, I'll use lipase.
The whey, of which not much less than the original gallon is left over, I put back on the stove and cooked down to gjetost. Took about 12 hours of simmer. Very credible gjetost flavor, a quite sharp caramel-like taste and about as hard as cream cheese. Stronger than the import I've bought at the grocery, and I didn't take it down so dark or so that it would set up so solid. A bit grainy. Gjetost is often mind of grainy, but I think I can whip it more before it sets and fix that. Have to read up. But that's not bad to get the mozzarella and 10 ounces of gjetost from a gallon of milk.
Total cost was $3.58 for milk
1.00 (less than) cheese ingredients
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4.58
Reasonably good mozzarella seems to run about $12 a pound.
Whatever USDA is reporting on as "mozzarella" when they report wholesale price runs either side of $2.50 a pound wholesale. (Kraft brick?) I think the deli fresh mozzarella at my local store is somewhere high of the midpoint between those.
Gjetost, mixed milk, runs around $8 per half pound. I made 10 ounces. I figure to lose a couple more ounces cooking it down hard. So I can't complain about the products of the gallon of milk and the short time involved.