Inspired by a friend while picking grapes this is my version.
1. Pick some organic grapillons with the permission of the vigneron. Grenache or Carignan from Mas Gabriel are perfect. Grapillons are small bunches from later flowering and are less sweet than ripe bunches. More importantly, vignerons don't generally pick them as their unripe green tannins makes red wine bitter.
2. De-stem the grapes in a clean bowl. Fingers are good at this.
3. Blend the grapes in a blender. This is quick but aggressive - quite a few skin tannins will be extracted.
For a gentler approach try treading them with your feet.
4. Sieve into a bowl. The juice can then be bottled (used plastic mineral water bottles or similar are ideal) and stored in the fridge.
The remaining skins, pips and stalks can be spread on the vineyard, although technically they should be left in a designated place to be collected by the local distillery.
To make a natural wine use ripe grapillons and after step 4 just allow the juice to ferment. You don't need to add anything else as I'm told it won't be natural, although bio yeast nutrients are acceptable. Using a closed glass fermentation vessel like a demijohn should reduce the risk of the fermentation going wrong.
The above makes deep rosé, although rosé from Carignan will look like red wine.
To make a deeper red wine wine delay step 4 by a couple of weeks but be careful not to over extract. For white try white grapillons. For sparkling wine simply use a pressure proof bottle and omit the fridge bit of step 4.