Is my starter good enough... or am I making the bread wrong?

Hey All,

Well after many attempts, I finally seem to have something that looks and behaves a bit like a home-made sourdough starter. I made it with wholewheat bread flour (strong flour) and water, generally putting in half as much water again as flour when feeding (so if feeding 100g flour, I added 150g water). This one seems to grow well, it gets reasonably bubbly when fed (after a few hours), smells nice and yeasty and in general seems to look right going by pictures I've seen in guides and posts here.

I made my first loaf from this starter yesterday and it has certainly made something that looks and tastes like bread. But I wasn't really happy with how it looked during the process and the loaf ended up quite dense. It actually puddled in the oven, sinking down and flattening.

The loaf I made was done as follows:

250 g starter + 100g Wholewheat bread flour and 150g water. Left for about 6 hours to develop. It bubbled and developed as expected.... looked rather like poolishes that I've made before when making baguette with purchased yeast.

Then, added 100g water and enough wholewheat bread flour to bring the mix together as a firm dough, which I then kneaded and left to rise for a few hours.

Knocked the dough out, put it into a floured basket to shape for about 1 hour. Then baked at high temperature on a heavy baking tray.

What I noticed, was that once the firmer dough was made, it did rise... but took a long time to do so and felt sort of clammy, heavy and sticky to the touch. It really just didn't feel right. One thing to note, is that it is winter so it's not particularly warm around here at the moment... 

What I'm wondering, is whether my starter is 'strong' enough to actually rise a dough properly. Do I need to go through some more feeding iterations to get it stronger? Or is my approach to making the loaf so far off, that it would cause the rise to be so unresponsive? Or do I maybe just need to find somewhere warmer to rise the dough?

Any advice would be welcome. I'll be fiddling about with it myself of course (half the fun is in working these things out) but advice on which direction to look in - or perhaps some indication of what sort of rising performance I should expect from a successful starter, would point me along the right lines.

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