what kind of starter to have if only to have one kind?

Rye, but any grain will do. second choice... wheat.  Depends on your available flour and what you like to bake.  I also slip my rye starter a little mixed flour once in a while to keep the beasties guessing.  Stays more well rounded and perky that way.

Your question is loaded with potential to start a discussion about preferences in starter culture and acid levels and flavor and on and on.

First you have to start somewhere and decide later if you want to change hydration or feeding schedule. I decided that I like a slightly firm starter. I feed 50g of old starter with 100g water and 120g Bread Flour. If I have been baking daily and the starter has been fed as above for a few days every 12 hours or so, it is healthy and active. If I don't want to feed it every day for the next week, I feed it and immediately refrigerate it for the next week or two. Any time I want to bake a loaf, I simply remove a 1 Tablespoon blob of the "Mother" starter and feed it up to the needed amount. This is called "elaboration" of the starter. In 1 or 2 feedings you will have all the active healthy starter you need.

Some people use different hydration levels for different reasons. I used to use a 100% hydration level because it was easy to know how much flour was in my starter for the total dough  calculation. Half of the weight of the starter is flour, half is water. Also, at 100% it's easy to mix and incorporate. Because it is a wetter mix, it is a more active culture, for a shorter time than a firmer mix.If you neglect a feeding schedule or forget to feed just one time at 100%, your starter will be worn out on the counter and flat. It isn't dead, just panting waiting for a meal. If you miss another feeding, you are on your way to hooch or an acetone smelling thin and sticky starter that needs to be brought back healthy condition with regular feeding. Not to worry, after just a few regular feedings every 12 hours it will again be happy and the smell will be coming back to healthy.

Another reason people use a specific hydration is for the flavor that the culture imparts to the the dough. With out getting too technical, there are 3 basic types of living things we care about in a starter. 1) Yeasts, 2) Bacteria that produce lactic acid and 3) Bacteria that produce acetic acids. The feeding schedule you use and the amount of food you supply (firmness) coupled with the environment or temperature that the living bacteria become used to over a period of time, influence the ratio of lactic and acetic producing bacteria and hence the flavor of the breads. Other things can also effect flavor such as timing and retarding the dough but the underlying culture population has to be there to create the desired flavor.

If you are just getting started using a natural yeast (sourdough), I suggest you follow Debra Winks advice on the starting of a starter and continue to feed it at room temp. for a couple weeks at 100% hydration.  Where you live has an impact on your room temperature and how quickly the culture will consume the new food. If you are near my house where it's -3 F degrees this morning room temp is 65F and a 12 hour feeding schedule is fine. If you live in the Land of OZ down under, where it's mid summer, a 12 hour schedule at 100% wouldn't be enough food and you would be underfeeding the culture. In this case a firm mix works better, for example 60% hydration. More food for the same water.

I tried to give your question a serious response. It is easy enough to change the hydration of a starter elaboration as you build it. It's also easy to elaborate a starter from a white flour culture to a rye or whole wheat flour culture. After just 1 or 2 feedings the new flour is essentially all the flour if that matters to you. Personally I don't think it matters at all if 10% of the rye starter is white flour. It does matter that it's active and healthy.

Hope this helps. If you have further questions ask away. There are many experienced SD bakers here who I'm sure will be happy to help.

Eric

wow, just what i was looking for!  i have a 5 year old la brea bakery  white starter and Eric, you have given me the easy way to transform it into rye or wheat. Many thanks!

I maintain a single rye starter at 100% hydration made from home milled organic ryre berries.   This starter is used for everything and is versatile by virtue of varying the amount of starter in any given recipe.  More starter equals more rye character.

Jeff

Without a doubt, I find a simple 100% starter to be most flexible.

It's easy to re-calculate to other hydrations or to refresh with rye or whole wheat.  

Also, my family is (unfortunately) averse to very sour breads and I find this starter remains relatively neutral.

Enjoy!

MommaT

I was never happy with the flavor of my home-made starter, even though it rose reasonably well.   Sooo a few months ago I ordered the Italian Ischia Sourdough Starter from Cultures For Health (www.culturesforhealth.com). There is more than one site to order specific strains/cultures, but I just took a chance on this one. 

This has been a wonderful starter for me,...far superior to any "wild yeast cultures" that I have ever grown.  The Ischia is very active,  strong/fast...but not as sour in the finished bake that the company implies.  Sourness in a finished loaf is also determined by more than the strain of yeast & bacteria though.

I start my culture out at 100% hydration every day.  I maintain a small Mother  by using 1/4 C EACH of starter, unbleached KA All Purpose Flour, and Dasani water. I always leave the starter at room temp, so it MUST be fed.   

Sometime in the late evening, when ever I remember, or am working in the kitchen...I add about another 1/4 Cup of flour.  This stiffens the starter considerably, even though the proofed culture is a little wetter than my "morning re-make".  I just got lazy about being fanatical. I don't worry about when to do these things...I don't worry if I don't get the formulation/ratio exactly right. 

  A couple days before I want to bake, I build the starter up to a bigger volume...still going by the same procedure.  100% hydration initially,..then only more flour at the end of the day.

If I want to make a different Mother Starter from my original culture.  I remove a portion, and re-build the newbie with whole wheat, or rye flour,...letting the new version stand on a counter, far away from re-freshed Mom.  This new culture will develop better if refered overnight.   I keep my original culture "pure", by being consistent with the type of flour, and bottled water.  Keep the various cultures covered, separated from each other and never-but-never share utensils while mixing from one culture to another.

If you have good strains of yeast & bacteria... you needn't be a total slave to the process of making good bread. You DO need to understand that these tiny little critters that we can not see, can be contaminated by other strains of "bugs" though.

What a thought! I might have room in the refrigerator-or on the counter, if I had only  1! I have several sourdough cultures at various stages of use and history as well as yogurt and several jars for kefir.Hardly room for the milk and eggs.