Starter Size Clarification

Ingredients
1

When I read posts about a 4L starter or go on Mr. Malty and they are suggesting a 3.5 L starter or something similar, exactly what does that mean?  Is that the amount of yeast produced by pitching into 3L of lower gravity wort and then removing the older starter (beer) and pitching the yeast or pitching all 3L of stuff or do I need 3L of yeast (I don’t think this is the case).

Please clarify what this means to you.
Thanks

2

Yes, in most cases it is best to grow the yeast first, decant the spent starter beer and pitch only the slurry. If you are just pitching, say, a 1L starter active you are not really growing any yeast.

3

It’s the total volume of liquid not expected yeast. For example I probably ended up with a cup of actual yeast from a recent 3 quart starter.