The lemon contribute to lower the pH of the sugar water so that foreign opportunistic bacteria and yeast don’t get a chance to invade your brew. The lemon peel is also high in calcium and is good for the Kefir Grains. Don’t squeeze the lemon juice into your kefir brew, this may have the opposite effect doing more harm than good. The idea is for a gradual pH drop and not a shock making the brew too acidic for your Grains to brew happily ever after. Adding lemon is not needed with every brew, if your grains are strong and become more with every brew it’s probably not needed. Traditionally some of the previous batch of kefir, enough to cover the grains will be added to the next brew.
The dried fruit adds additional minerals and other micro nutrients that may not be supplied by the sugar or water. With Water Kefir nothing is set in stone and you are your own brew master experiment and learn from the feedback you get from your Kefir Grains. Good feedback from the grains will be when your Kefir Grains Grow and become more producing more tart and bubbly kefir. The fruit, blackstrap molasses and Consentrace Mineral Drops serves the same purpose.