I used to have two problems. The first was that I didn't bake frequently enough, so my culture would become essentially dead. The second was that I was getting rid of excess sourdough culture.
Currently I maintain 2 cultures. 1 spelt and 1 whole wheat. They taste really different.
Here's what I do to keep them vigorously active.
About twice a week I make sourdough pancakes, one time with each culture. When I take the culture out, I replenish it with fresh flour and water.
Sourdough pancake (more like crepes) Recipe:
1 cup 100% hydration sourdough culture
1/2 cup water
1 large egg.
1) I put all of this into a 1 quart mason jar. Shake it vigorously.
2) I use a cast iron pan, heated up to about low-med.
3) Pour the liquid batter onto the hot cooking surface. Flip when the edges start showing that they're cooked.
4) Top with favorite pancake toppings. I personally use crushed walnuts, cinnamon, maple syrup, whipped cream and some fruit like banana, berries, mango, etc.
It is a quick cooking breakfast. And no fermentation time is required.
This makes a very thin crepe like pancake. If you want it thicker, cut back the added water to 1/4 cup or less. Maybe even just the starter and egg.
This way, I'm not forced to bake each week, and I don't throw out anything. I'm a little frugal with some things, especially food waste. My grandma really made me feel back about starving children in other countries.
What methods do you use to maintain your culture?
I came to much the same conclusions. I refresh my (one) sourdough culture once a week by mixing one cup ww flour, one cup water, and a spoonful of old starter, letting it sit for an hour or so, and then refrigerating it for another week.
The leftover starter gets turned into pancakes. I mix the starter with some Krusteaz ww pancake mix, some eggs and milk, and let it sit overnight. I don't measure; I go by instinct. By the morning, the starter has digested the pancake mix and the resulting pancakes are light and tasty, without the grainy taste I get from the same pancake mix without sourdough. If I leave the mix longer than overnight, it develops a pronounced sourdough flavor. I don't like that in pancakes, but perhaps others do.
Seems to work best for me if I do all the mixing on Saturday night; Sunday morning is then the once-a-week pancake morning.
I end up with more pancakes than I can eat, but I like them just fine cold, plain, as hand food with a cup of milk or chai.
All of the above ... but add a couple tablespoons of oil or melted butter, make the batter little thick and pour it into a hot waffle iron. Add blueberries or pecans or the add-in of your choice. Voila, you got yourself a bit o' heaven on a plate. The starter definitely adds a depth of flavor that you cannot beat.
As a bonus: Waffles freeze wonderfully, and come out of the toaster hot and crunchy.
"I am not a cook. But I am sorta cooky."