[HowTo] Making my own yeast water culture from raisins and organic coconut sap sugar

I have always been an avid home baker. There is something about the whole process of bread making by hand that is strangely therapeutic in my opinion. Maybe it is the fact that it requires a lot of patience or that I am just a sucker for delayed gratification. I have decided to step up my bread making game by attempting to culture my own wild yeast water from raisins and with just a little push from some coconut sap sugar dissolved in the water. Of course, you can make a sourdough starter directly by just mixing flour and water and leaving it exposed to the air at home, but I have decided to go this route. Depending on your specific home conditions, there is a distinct community of yeast and bacteria naturally present in the air but do note that not all yeast and bacteria (mostly lactobacteria) strains produce a tasty sourdough starter. By choosing to make it with raisins, you will (at least that is the underlying premise on going this route) naturally get yeasts that are naturally present in the grapes before drying and which I have heard is mostly the type you want for leavening bread (ok, that's purely speculation on my part so don't quote me on that).

The process itself is very straightforward. Just add some raisins (preferably organic ones if you can get it) into a container with a tight-fitting lid containing purified drinking water (if your water district chlorinates the tap water, I would suggest boiling the water and letting it cool to lukewarm/room temperature before doing this), add some sugar, and wait for a couple of days while opening the container to let the mixture breath and shaking the container several times per day to prevent the growth of molds. It is that easy! Then you just wait until you see some bubbling in the liquid and most of the raisins float to the surface. When the yeast is properly active in the liquid, the container will let out a very satisfying hiss when you open the lid signifying built-up pressure from the carbon dioxide formation (mostly from the yeast eating up the sugars). The gasses escaping will smell a bit fruity with a slight hint of yeasty smell (or it can also have a boozy smell depending on how long you have been keeping the fermentation process going).

Stabilize the yeast water by removing about half of the liquid from the container and add a solution of more sugar with a bit of sea salt (non-iodized if you have it) and place it into the refrigerator (the salt will slow down the fermentation - the objective is not to have the fermentation process be completed like in making wine but in keeping a viable batch of yeast available for your needs at any given point in time so slowing the process down by cooling and adding a bit of salt is essential). You can "feed" this by repeating the stabilization step once a week but remembering to shake the container at least once a day and opening the container to let it breathe and relieve excess pressure.

There is no one way of doing this and if you want to know my particular method, the following are the specific measurements I have chosen:

Initial setup
600 ml capacity plastic soda bottle (food grade PET)
300 grams of purified drinking water (avoid chlorinated water)
15 grams of raisins (preferably organic ones)

1/4 teaspoon of organic coconut sap sugar (just enough to jumpstart the yeast activity)

for stabilization/subsequent weekly feeding
150 grams of purified water
1 teaspoon of sea salt
15 grams of organic coconut sap sugar

Also, check out this video for the step by step instructions: