One of the things I wanted to learn when I joined this forum was why some of my cheeses came out as Swiss cheeses, and why others didn't. This year I did figure out that I can control for Swiss by opening and closing my kitchen window as I make cheese. It actually works quite reliably; open windows = Swiss cheese, closed windows = no Swiss cheese. That means that wild proprionic bacteria is floating around in the outdoor air of my farm. But I still wondered where it was coming from, what causes it to get into the air. I had a real "Aha!" moment when I read a post from linuxboy about the people in the Swiss alps gathering clover to make a tea to add proprionic bacteria to their cheese. Perhaps the clover pollen? I planted the stuff all around the house about 15 years back, so I could harvest it for tea. So with closed windows, I wanted to see if the clover tea would make a cheese "go Swiss." I chose the Red clover, because I am already familiar with using it. (We also have several other types in the yard.)
I used fresh flower heads from the yard and put them into tepid (maybe 100o) water, and soon it smelled very much like perfume, very sweet. The buds were floating in the top if the water, so I pressed them against the sides of the bowl with a spoon to get the water all the way through them and make them sink into the water. I left the flowers in the water for about 1 hour until the smell changed from sweet to herbal.
I used a Romano recipe because they are the ones that most often make the best Swiss holes. I added 7 oz. of strained clover water to a 2 qt. batch of Romano, at the same time I added the powdered Thermo, and used the usual waiting time before adding the rennet.
Result: A terrible curd set. It took forever to get a clean break, and even then it was a much softer clean break than I normally get. I lost a lot of solids in the whey and that left me with fewer curds and a much smaller cheese after it was pressed. In hindsight, I do not know if this was because of adding too much liquid to a small recipe, or because I was working with a new bottle of rennet and hadn't yet figured out exactly the right amount to put into the cheese, or if adding that much water cooled the milk and made the Thermo culture grow slower.
I pressed the this cheese by hand under the whey in the cheesecloth before putting it into the press. I kneaded it to get out any air and pressed together the curds. At the time to flip the cheese over in the press it stuck like glue to the cheesecloth and I had to use a second cheesecloth to put it back into the press. This cheese did NOT plump up in the way of a Swiss cheese and I do not think I will have any holes or be a Swiss. It doesn't cut open yet for another few weeks, so I am still waiting to see how it will taste. But since it didn't plump, I don't think I'll try such a light tea as an inoculant in the future. It needs to be stronger.