As far as I can tell, there are two types of "good" food Vines: those that are funny or strange, and those that are actually helpful. The helpful ones are usually recipes or tutorials, like how to make a pie lattice crust.
In order to create a successful helpful food Vine, there are a couple things to keep in mind:
The first is that it should be very simple; if it's a recipe, it shouldn't have a lot of ingredients, and if it's a tutorial, it shouldn't have a lot of steps. A six second video shouldn't be the place to show off your culinary prowess. The second thing to keep in mind is that if possible, try to write what the ingredients/steps are or say them in the Vine. This will make the video clear.
Something that doesn't matter compared to normal food video and photography is that the Vine really doesn't need to look pleasing or appetizing. Nobody is going to Vine for beautiful food photos, although stop motion Vines are definitely a bonus.
Here are a few examples of some successful, helpful food vines:
1. Lattice Pie Crust (First Video, Above) - Tuuva Harjanne
2. How To Clean Your Grill - Bon Appétit - That's vegetable oil they're putting on that paper towel BTW.
3. Mushroom Burger - David Finley - Looks easy, doesn't it?
4. Rolo Pretzel Bites - AnnaBeth McGovern - Simple recipe, perfect for Vine.
5. Tzatziki Sauce - DFry DealiciousCooking
6. Waterloo Cocktail - Chris Perez - I love that Perez lets us know the ingredients and amounts used in the description of the Vine.
7. Pretzel Folding - Wee Eats
8. Chicken, Corn, Green Beans - Maranda Orth
9. Nutella Filled Cookies - Graham Tan
10. 6 Second Green Dream Smoothie - HealthyBatch - Smoothie Vines are probably my favorite types of instructional Vines. All you really need to see are the ingredients.
(Videos: As Linked)