Correct, it doesn't hurt the ff to be submerged, but I can't figure out why you'd want to, especially if you are fermenting processed feed. Now, if you are fermenting whole or even cracked grains, it wouldn't be much of an issue to strain the grains out of the water that's covering them. But, it's simply one added step that is not at all necessary IMO. And straining processed feed is really a sloppy messy undertaking.
SCOBY = symbiotic culture of bacteria and yeast. It comes from the air. Just like the old timers used to have their sour dough cultures (they didn't run to the store to buy yeast, but kept a culture going that was simply seeded from the air in their home.) That is what causes the fermentation. Many folks see a white film on top of their FF, and they panic. They assume that it is mold, when in fact it's a nice healthy layer of SCOBY. I've seen the white film, sometimes it is more tan or greyish depending on the source of feed, age of ferment, amount of stirring I've done, and ratio of water. It's all good, and gets stirred back in or even scooped off the top to "seed" my other bucket.
True mold will be black, or grey green and you can even see the cloud of spores rising up from it if you blow on it. You might see hair like filaments growing from it. If you want to see some mold to do a comparison between mold and scoby, I'd be happy to take you on a fridge tour, about an hour before I clean it out! Actually, mold can come in a lot of interesting colors, but it's very distinguishable from scoby.
I make my ferment simply by filling a bucket 1/2 full of water, and adding almost the same amount of dry feed. Stir it up, and wait till it bubbles, or puffs up. Mine is about as thick as: drop biscuit dough, thick cooked oatmeal, or soft serve ice cream. It is thick enough that I have to work a bit to stir it up, and the ladle stands up in it. It holds it's shape when I plop it into the trough. When I feed out a bucket, I hold back a cup full (more or less) and then simply refill with water and feed. And, really, the ratio of water to feed is not rocket science. If you mix your ferment and it ends up being more soupy than the girls like, simply add an other scoop of dry feed when you serve it up. If it's too dry, it will still ferment ok. But... sometimes when I make it too dry, I add some more water to it when I serve it up... to get the consistency that I like. I'd rather have the ferment too wet, and have to add more dry, than have it start too dry and have to water it down. Of course, the worst offense is when I'm doing it in my house in the winter, and I've put too much in my bucket. That's a learning curve right there: I've learned to keep something under it to catch the overflow... or cut back on how much feed goes into the bucket to start with!!!
