One the best way to dhh in this is make a 1 gallon starter with this. Then use this one gallon starter to pitch into 5 gallons.

Like most things in life the answer is “it depends”. I believe that you would need one kit to make a one gallon batch. Trying to make five separate one gallon batches then you would need to purchase five kits (if you are starting kombucha brewing for the first time and are determined to make five gallons on your first try). However if you are patient each 1 gallon batch that you brew will produce one new scoby and starter liquid. After a few batches you can brew five gallons easily plus you’ll get some experience with the process. If you are trying to brew one large five gallon batch then you’ll need minimum 5 cups of starter liquid and scoby (five kits). It can be done but I don’t recommend this until you get some experience brewing kombucha. Good luck and may the booch be with you.

It will grow with time. Mine grows to the size of the jug it is in (and about 1/4" thick in one 1 gallon batch. I think this could do a five gallon batch with enough time but personally I'd grow it to that size first... or buy at least 3...