30+ years ago the kits we had in the UK were probably purchased from Boots in a tall can of mixed grape and made about a gallon of wine. To be honest they were questionable at best and many people preferred to make country wines like Plum, Dandelion or Tea.
Today the kits available Beaverdale, Connosouir, Kenridge and Called Craft to name but a few come in gallon or five gallon kits with wine juice concentrate of the grape variety that is used to make the real thing. If you follow the instructions then you will get a quality wine that tastes as good as what you might buy in your local supermarket or wine shop.
I have done blind taste testing sessions by purchasing say a reasonable bottle of Merlot or Rioja pouring in into blank bottles and then presenting them with my home made kit wine versions. The results have always been quite close and more often than not the kit has come out on top. So £8 shop wine against my £1.50 kit wine! you decide.
Kits come invaring qualities from £40 for a 30 bottle kit to £80 for a better quality kit, so you need to consider what quality wine you want to drink. I suggest trying the same type of wine Merlot for example from two or more different kits and do you on blind taste test.
I will be adding some short videos showing how these kits can are made up exposing the process and comparing the results.