Loose highly active and unsalted sponge, a small amount of starter is left to proof for hours inside a jar until it foams. The watery sponge foamed quite a lot, the bulk 1/4 of the jar foamed to the top, proving the starter extremely active.
A few tablespoons of active sponge is spread thinly over a plasticine sheet for easy removal once it dries and breaks into flakes.
But why bother?
For backup. In case I forget to reserve sponge for new starter. To ensure my collection does not disappear. In case my starter dies for some reason, most likely neglect.
The remainder of the jar of starter is mixed with additional water and sufficient flour to form a thick sponge but not so much flour as to form a sturdy dough. The organisms will produce more liquid as the sponge proofs and I do want the dough to be wet to accommodate a high-heat and closed clay cloche technique of baking. This is loose, wet, for bread dough and over days in cool storage it will become even wetter. It will be held until the whole batch shows signs of leavening and then the whole bowl will be inserted into the refrigerator to ferment over days. How many days will determine the strength of the sourdough. If baked immediately you will notice a great difference between this and ordinary bread due to its complexity, but held to ferment over just a few days will produce a difference in strength, complexity and flavor that is quite extraordinary.
After this proofs for a few days and develops intense flavor and before it is salted then a small portion will be reserved to inoculate the next batch. That small portion will be fed and refreshed in a jar and brought up to full activity before being put to use.
Update: This is a few hours later. Ordinarily sourdough would take 8 to 12 hours to pervade and lift this amount of sponge. This Maui starter did this in just a few hours, about 1/3 to 1/4 the usual amount of time. It surprised me. The bowl was placed in the refrigerator for cold storage and fermentation. It can be baked right now and it would be excellent. But in a few days its flavor will develop even more strongly. It is a powerful culture.
You can see that the bulk more than doubled. Usually they cannot go this far and almost never this fast. This is at room temperature. This means that I can probably get away with including more than the usual amount of whole wheat flour.