Wayne - what are you doing with all of that whey???
I make Ricotta with every drop of whey I generate and average about 6 ounces per gallon of whey. I sell it to friends for $6 a pound (packed in 30 ounce containers). That's higher than the prices at the grocery store but everyone knows it's super fresh. I do 3.5 gallon batches, so that's around 21 oz or around $8 a batch. I pay $6 a gallon for milk ($21 a batch) so the FREE Ricotta pays for about 38% of my milk. So my net cost is just $3.72 a gallon for my milk. I get around 1.2 pounds of hard cheese per gallon so my net cost is around $3.10 a pound.
So, for your 25 gallon batches, that would yield around 150 ounces or 9-3/8 pounds @ $6 would generate $56.25 a batch for you. That's over $2 a gallon in quick return.
From a commercial point of view, that's pretty significant.
One caveat though. I am using really high quality raw Jersey milk, so I get a great yield. I also add a little more fresh milk back into my whey to boost the yield. Your yield might be lower depending on your milk, but it is still bonus money.