In my last blog, I discussed getting a sourdough starter activated & ready to use to create lots of delicious fresh sourdough products. Today I am going to talk about some of the things which may go wrong with your starter, (or which you may think have gone wrong), & how to rectify them.
So, the clue is in the above comment there in brackets, "you think may have gone wrong"!! There are several questions which I am often asked about regarding "problems" with starters. The first thing to remember with your starter is that it is full of extremely resilient yeasts & lactobacillus bacteria. They are really quite difficult to kill off. As I stated at the end of my last blog, if you followed the instructions to the letter, then you should have a starter which is ready for you to use to make your first loaf with. It should be bubbling away & smelling kind of fruity & slightly vinegary, but if it isn't do not despair. Unless your starter has been contaminated with some fatal fungicide, (found in non organic flour), some residue of cleaning fluid, perhaps on the bowl or container you are keeping it in or has overly chlorinated water in it, which will kill off any good, as well as bad bacteria present, then I can guarantee your starter will be very much alive.
So what's going on? If it looks a bit flat, smells really most unpleasant & sour & has a distinctly unattractive looking grey liquid swishing about on the surface the simple answer is excess acid. Over fermentation has occurred & the lactobacillus has taken over. It is important to appreciate that your starter is actually a community of active organisms which must live in harmony to survive. Lactobacillus bacteria produce 'bacteriocins' which destroy competing & potentially harmful bacteria, but they also produce anti fungal properties. Wild yeasts present in the flours we've used, can tolerate the acid conditions produced by the lactobacillus, whereas mould growth is inhibited so this is obviously a good thing. The problems start when the starter becomes too acidic & the yeasts are unable to produce carbon dioxide to make the starter bubble & yeast reproduction will slow down too. Do not despair, however! The simple solution to an over acidic starter & revive the yeast is to reduce the acidity. This is done by taking a small amount of the acidic starter & adding much larger amounts of flour & water. This refreshment process is essential. Do not think a small amount of flour & water will cut it, because it wont. You need to dilute the acidity & this can only be done with much larger amounts of flour & water than starter, to introduce the necessary yeasts back in to the starter & rebalance things.
Take 30g of old starter & mix with 180g of warm water, (about 30 to 35 degrees celsius), then add 90gms of wholemeal wheat or rye flour. Mix well, cover & leave for 12 to 24 hours. It should, after this period, be fermenting nicely. You will now have two starters, an older one & your refreshed one. Keep your old one in the fridge until you next want to use it to make bread. It will become increasingly acidic, which is fine as it will keep it more stable & mould free for as long as you want it too. When you next want to make some bread, you simply need to follow the refreshment process with your old starter again. Your refreshed starter can now be used in the first stage of actually making a loaf.