Too Sour

Hi

New member here, though I have been lurking and reading for while.  About a month ago decided to have a go at sour dough, so made a start from the '101 tutorial'.  It took a bit longer than expected, but it is the winter, but now nicely rises in a few hours.

The first loaf I made took forever to rise, and in the end I ran out of time, and got the brcik I deserved. The next two have been risen better, but they taste too strongly of vinegar - you end up tasting it for the test of the day!  Now our house is quite cold at this time of year, so I have been using our warming drawer on its lowest setting to move things along a little.  Do you think this is the cause of excess vinegar?  Texture of the loaf is quite open , with a few large holes, but a bit 'rubbery'.

For the record my recipe is 100g starter, 250g flour (strong white), 300ml water, left overnight.  Next morning 300g more flour, 12g salt and .5 tbl o oil.  (My starter is quite stiff, and I keep in the frdige, feeding on Wednesday night if I start to bake on Friday night.)

Thanks

Lloyd