Wine in Graveyard Keeper is a very valuable resource. You'll need it for a few missions, i.a. for Gerry and the Inquisitor. Additionally, wine is expensive so making it is a good idea - you can sell it and get lots of money. However, if you don't want to focus on growing plants and expanding your winery, you can buy wine from Horadric.
Buy wine in the bar
To buy wine from Horadric you must have 2nd level shop unlocked. To do this, you need to sell him a lot of things, do quests for him, and buy food from him. A detailed description of the shop expansion can be found on a separate page, called "How do I upgrade shops?"
You can buy wine for 5 silver coins. It all depends on their quality. He might even offer you a wine with a golden star, but that's not viable. Remember, however, to buy silver wines for quests.
Create your own wine
Winemaking is time-consuming and is initially pretty expensive. If you can manage to develop the right way, you will be able to create your own wine. Just buy the grape farming skill. It's the Farming and Nature branch.
In order to plant grapes you must go to Vineyard. To get access to the vineyard you need to unlock the garden and open the passage to the Witch Hill. Inquisitor arrives every week, on every Day of Wrath. You will meet him for the first time on his way to Witch Hill during the first Day of Wrath. You will start by chatting with him. After that, he will ask about your intentions. Then, he will let you into the Witch Hill. From this moment, you will be able to get to the Vineyard and plant grapes there. You can buy grape seeds from the Merchant.
You will have to go to Vineyard around the clock through Witch Hill. However, you can open another passage. It is located above your house. To open it you must have 2x flitch, 2x complex iron part and 10x wooden wedge. This will allow you to get to the vineyard quickly.
After buying the grape farming skill, you will be able to buy a machine for processing fruits - the Vine Press and Winemaking barrel. This will let you juice apples, grapes, etc. The device can be created with 12 flitches, 4 complex iron parts and 10 pieces of stone.
With Vine Press you can get juice from grapes, apples, etc. You will create this machine with 12x flitch, 4x complex iron parts and 10x piece of stone. Winemaking barrel can be crafted with 12x flitch, 5x simple iron part and 7x nails. Winemaking barrel requires 2 juices created in Vine Press.
In order to get 1 grape juice, you need 15 clusters of grapes. Pay attention to the quality of grapes and don't mix good ones with bad ones - you will only get regular wine, not the best.
In order to create 20 bottles of wine, you need 2 grape juices.