Water Kefir Grains with Unknown(ish) History
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One of my coworkers recently got into making fruit juice kefir and I expressed how I had been fermenting veggies for a couple years now but hadn't gotten around to experimenting with kefir grains yet. Yesterday morning, as a gift, she brought me a juice bottle with water kefir grains in apple juice. They apparently split up their kefir grains the night before and put these little guys into the juice then. She said it was likely ready to go into the fridge already last night, which I ended up doing.
While it was sitting on my desk yesterday, it was clearly very active because I had to burp it every 40 minutes or so. My question is... what should I do with these guys since I don't know their full history? I've read that juice is hard on the grains, so I'm wondering if they should go into some sugar water? Should I strain off this juice to drink, get them into sugar water, and go from there? I've read the transition back to sugar water can make an unpleasant drink, so would refreshing that a few times somewhat reset them? I would love to get to a point where I can split off my own kefir grains to maybe keep both water kefir and juice kefir going. But if this is a situation where once they're in juice, they must stay that way, that's fine, too.
Long story long... I'm wanting advice on how to best care for Kefir Sutherland so that I can get a long, happy, and healthy life. But because I don't know his full history, I'm wondering if there are things I can do like a "kefir detox" to give him the best chance. I was not quite ready to be a Kefir Mom, but here I am.
I'm not sure what other relevant information might be helpful, so please ask if more information is needed.