Pitched 2 separate 5 gallon batches... couple questions

I am new to this and I've always wanted to do it, but was a bit intimidated, so I didn't. I have several orchards nearby with lots of fresh cider, so this year I told myself it was time.

I've got two 5 gallon batches going and the first batch has been going 24 hours and the second batch I just did around 8pm EST.

The first batch had a nice krausen going, but it seems to have dissipated and now there are bubbles/foam on top. I was nervous it was starsan because it looks just like it, but the more I read, I don't think that's the case. So... are the foam/bubbles normal?

Second question, how long do I let it go in the primary before I start taking some gravity readings? I don't want it to get bone dry on me, but at the same time, I don't want to chance spoiling a batch by messing with it more than I have to.

Thanks!

I'm fairly new as well but bubbles are totally normal. Yeast eating sugar emits co2. That's why it's bubbly. Did you add sugar? Take a reading in a week or two. If you got an og then calculate your alcohol content. I'm still new so not quite sure how you would stop fermentation. (I'm just counting on my yeast to eat up all my sugar) but a week to two weeks should be cool to take a reading.

That foam and bubbles is totally normal. Good sign of a healthy fermentation going strong.

Since this is your first batch I suggest taking SG readings every couple of days. Taste and smell each sample, keep an eye on the airlock bubbles and the appearance of the cider, how much sedimentation, clarity of the cider, krausen etc. Record all readings and sensory ques. By the time you make you're next batch you will have a much better non-invasive way of understanding what's going on in your fermentation vessel.

Don't worry too much about contamination. Along with proper sanitation, the vigorous fermentation you have going will help protect your cider.

Looks like you're well on your way!