Traditionally, buttermilk was "milk" that was left over from butter making. That means that *all* of the fat has been removed and probably a little of the protein as well. If you buy "buttermilk" in the store, usually they use partly skimmed, or even full fat milk and add a mesophilic culture to it. This is one of the big reasons that I don't like recipes that add a lot of buttermilk to them -- it's pretty hard to know what the original author intended. If you look at the beginning of the video: lo and behold! "Cultured Buttermilk 0% M.F". Not only that, but look at the milk he is using: "Farmers' 3.25% M.F."
I know Pickles lives in the UK an standardised milk is 3.6% fat. Let's assume full fat "buttermilk" as well. So in Flound's recipe there is 4000 * 0.0325 grams of fat = 130 grams of fat. With UK standardised milk and full fat "buttermilk", the amount is 5000 * 0.036 = 180 grams of fat -- almost 50% more fat in Pickles's version. So that potentially accounts for quite a bit of the difference.
There are actually quite a few traditional cheeses made this way, that tend to differ based on the temperature that you are setting the curd. If you set the curd at about 50 C, you'll get a cheese with a pH of about 5.3 -- this makes Ayib. If you raise the temperature up to 92 C, you'll have a cheese a bit over a pH of 6.0 and you will also get a higher yield because you get all the whey proteins as well. This is essentially whole milk ricotta/ricotone -- but there are many, many other names for it. At 80 C, the pH is about 5.8 - 5.9 when it sets the curd and depending on a variety of factors, you will get some, all or none of the whey proteins.
However, look at the video. Flound's whey is completely opaque. That's because he did *not* add enough acid to get all of the cheese. The pH will be higher. If he had upped the temperature after that point, he would have gotten a much higher yield. If Pickles added enough acid to get the pH down to 5.8, for instance, the whey would be fairly clear (or at least cloudy -- unhomogenized milk produces cloudy whey, usually).
But let's do the math:
Flound: 690 / 5000 = 13.8% yield with an average milk fat in the milk of 2.6%
Pickles: 1300 / 5000 = 26% yield with potentially an average milk fat of 3.6%
There are a couple of reasons for the difference. One is the fat level. The other is that this kind of cheese gets maximum yield at a pH of about 5.9. Also Flound clearly wasn't extracting all of the cheese from that whey. Even saying that, 26% yield is unreasonable for this kind of cheese. It means that the cheese was quite a bit moister. I'm *guessing* that Pickles drained it in the fridge, which will interfere with the draining. There may be other reasons.
But actually, as I type this:
full milk 4L
heat medium/low to 80°C [75-85°C]
cool to 32°C [30-35°C] <----- This step is not in the video!!!
add 1L room temp cultured butter milk
So, you are making a completely different cheese Pickles ;-) I leave all the other details for interest sake.
As to the salting level -- the higher the moisture content, the less salt you need. It really is amazing the difference.
