Farmer's Cheese is 1 Gallon pasturized whole milk from the store, 1 C of buttermilk from the store, and the juice from 2-3 lemons, at room temperature, curdled, strained through cheese cloth with a weight on it overnight in the refrigerator.
This is how you made your whey?
This would probably fall into a fermented cheese, almost a yoghurt cheese with the lemon juice helping it along. Sounds delicious!
Cultured buttermilk usually has both yeast and bacteria in it, all good stuff. There shouldn't be anything wrong with it. Without the cultured buttermilk, I would hesitate to say it's safe because the milk has been pasteurized and it leaves it open to any opportunistic invisible beasties, some of which might be harmful. However, adding a starter culture like cultured buttermilk, makes it unlikely unwanted invisible beasties might invade the whey.
Why would it become gelatinous? Good question. Scratching the back of my memory, there are yoghurt cultures that can create gelatinous results. Villi is the first that comes to mind, but there are others. Think about the jelly 'grains' that kefir makes - there is something in milk that will naturally ferment into jelly, but what and why it happened here? It's a good question. There is usually proteins left in the whey, maybe they reacted with the live culture from the cultured buttermilk?
I keep saying 'cultured buttermilk' because buttermilk used to refer to the milky liquid leftover from churning butter, but now it
also refers to a cultured milk product, made something like yoghurt. Of
course there is also buttermilk from making cultured butter... one word, so many meanings.
One of the great things about ancient crafts like cheesemaking is that the same words have a whole range of meanings depending on where in the world the recipe originates. Since we are using English words, in England up to about the middle of the 20th Century, the dialect could vary drastically from village to village. I saw a BBC film a while back where they were talking with fishermen from the part of Suffolk where my dad grew up. He could understand the language easily, but even the other British viewers needed subtitles. Even today, the meaning of the words and phrases depends on where you are and what decade we are talking about. Decimate means to reduce by one-tenth in most of the world... up to about five years ago, whereas now, especially in North America, it used instead of the verb desolate, or to almost utterly destroy and consequently desolate is now hardly ever used as a verb. Luck out, until about 20 years ago, meant to be out of luck, and still means that in much of the UK, whereas in North America, it means to be in luck, or as they say in the UK, luck in. It's one of the things I love most about ancient day to day crafts like cheesemaking, is that any attempt to standardize the language has proven futile because there is so much regional variation and tradition that surrounds it.
'Farmhouse cheese' in the middle ages, was almost always a rennet-based cheese. Later on, it moved towards being a fermented cheese, like the buttermilk one you describe. In more recent
books, 'farmhouse cheese' is an acid and heat cheese like paneer. The same with the way ricotta is used now - before it was a specific kind of whey-based cheese, but the books now use this word to described any cheese of a similar characteristic. Clabbering can mean from raw milk ferment, it can mean from a starter culture, or it can be used to describe the result rather than the method and talk about a chemical rather than a fermentation reaction. Old word, lots of possible meanings.
The frustrating thing about the language is that it makes discussing cheesemaking with people who have read different books, or practice different regional traditions, a bit difficult as we can end up talking about the same thing but not realize it because the words we use are different.
Many people think of a SCOBY as being a Mother - it is not. A mother is a SCOBY, but a SCOBY is not necessarily a mother. A mother is like the kombucha '
mushroom', vinegar mother, or kefir 'grains' and is often something distinct from the finished 'brew'. A SCOBY is a bunch of bacteria and yeast living together and liking it. This can be separate like a Mother, or it can be the finished product like yoghurt. It is usually balanced - meaning that if one keeps feeding it, the SCOBY can continue indefinitly. Commercial yoghurt starter isn't always considered a SCOBY, because the bacteria and yeast are not co-existing in ballance and the culture weakens over time. Traditional yoghurt like Villi or Fil Mjolk, is a SCOBY. (in some parts of the word, Mother and SCOBY are completely interchangeable, and mothers don't have to be a seporate thing like a 'mushroom' or 'grain') See what I mean about words? Aren't they beautiful? A bit confusing, I grant you, even with modern ideas like SCOBY.
There must be some yeast because of the effervescence
The effervescence is from a build up of gases, most likely
CO2. Both yeast and bacteria create CO2 as a byproduct of their ferment (ferment farts). So yes, it could easily be from yeast, but it could also be from bacteria. Sounds like from what you describe, it's from both.