I make my own kefir and brew my own kombucha because they are expensive to buy, but really easy to make and don't take up too much space in my tiny kitchen.
When I had my allotment I used to make sauerkraut in a big German fermenting pot that could swallow a couple of big white cabbages, but then it all needed to be transferred into jars and kept cool until it was eaten, and sometimes it managed to go soggy and unappealing before I got round to it.
Since moving back to the UK I order the kimchi and sauerkraut from lovingfoods.co.uk - they send me 8 jars every 6 weeks, and sometimes add a jar of Vadasz Super Beet Kimchi to the online shopping trolley when it is on special offer.
I make around 3.5L of kombucha every ten days, using a mix of 6 organic black teabags and 4 teaspoons of high altitude purple tea from Kenya, with 300g of organic sugar, and filtered water, in one of these 4 and a quarter litre fermenting jars https://www.amazon.co.uk/gp/product/B08P9VVSDD/ and this scoby https://www.amazon.co.uk/gp/product/B01MY91JH2/ that I bought in April last year and still haven't killed it yet. After 10 days in the jar I fill the second jar with tea, filtered water and dissolved sugar, move the scoby over to the new jug, top it up with a bit of the previous brew and use a jug and funnel to decant the remainder into these bottles that come with squares of muslin and rubber bands to keep fruit flies from skinny drowning themselves in the brew.
https://www.amazon.co.uk/gp/product/B01LB1862A/ I let the bottles sit on the kitchen counter for a couple of days to build up a bit more fizz and then store them in the fridge.
The plastic funnel I had was too big to fit inside the necks of the half litre bottles so I had to invest in a smaller funnel https://www.amazon.co.uk/gp/product/B07ZFXWMJ6/ to fill the bottles without mess.
The recipe that came with the scoby said to steep the tea for 30 minutes, so my first couple of brews were bitter and tasted overpoweringly of stewed tea. Someone else said that if you use high quality tea and enough of it then steeping for 10 minutes is sufficient to keep the scoby alive. Since I started doing that my kombucha tastes lovely. It's quite sour because the yeasts and bacteria in the scoby convert the sugar to vinegar, but fizzy and very refreshing. At first I'd add dried berries to the bottles before decanting it from the jar, to add different flavours, but it was a bit of a faff, and I really like the taste of plain kombucha now, so add the dried cherries, goji and sea hawthorn berries to my breakfast porridge instead.
I brew the tea earlier in the day and make sure there is plenty of clean fresh water in the brita filter jug, the mix of tea, sugar and water has to be room temperature before you transfer the scoby to the new jar. You have to wash your hands really carefully before grabbing the scoby and hauling it out and into the new jar, so as not to infect it with any unwanted organisms. Then stir the contents of the brewed jar before pouring it into the jug that is used to pour a bit into the new jar and decant the rest into the bottles, because the yeasts tend to settle towards the bottom of the liquid and you want them to be evenly mixed so that the new jar gets a proper starting boost and all the bottles have the same mix of yeast and bacteria.
I can get filling the new jar, transferring the scoby, stirring, bottling, and washing up the old jar, jug, mixing spoon, funnel and muslin, and have the fresh brew moved to the back of the counter and all the bottles lined up in front of it, on auto pilot in under 30 minutes. Considering how much kombucha costs in the shops (and never knowing if there is anything left alive in there when you drink it) the jars, bottles and scoby was one of my better investments. The home made stuff fizzes with life, and even people who recoil at the idea of fermented foods find it quite refreshing and pleasant to drink. I feel like a hobbit alewife each time I hang the freshly laundered muslin cloth to dry, and admire my row of bottles.