Optimising mash souring (sourwort/flas)

When it comes to successfully making sourwort/flas for baking, there are four parameters to be taken care of in order of diminishing importance: (i) lack of O2, (ii) initial pH (iii) temperature and (iv) time.

(i) One common way brewers (and not only) use to achieve this is by CO2 purging. For this purpose I use an inexpensive gadget i.e., a bicycle CO2 inflator to pour CO2 over the mash (do this gently as to avoid gas turbulance) and purge the head space of the souring vessel. Then an airlock of some kind must be fitted as well to avoid expansion accidents.

(ii) This can be done by adding to the mash a variety of food-grade chemical acids like lactic (most common), ascorbic, acetic (vinegar), tartaric or alternatively use a backslope from the previous sourwort batch. The amount used for each one is determined by aiming for an initial (before souring starts) pH near the 4.3 point. This is called chemical or technical acidification as oposed to the natural/wild bio-acidification that proceeds during souring.

(iii) Souring must take place in the neighborhood of 110F. Here, one can be more relax with the accuracy, as compared with the above two.

(iv) The soured liquor can be strained clear from the mash after 36 to 48 hours. No harm if left longer, it will simply become more sour (up to a point). If so, adjustments must be made in the bread recipe, not to hurt gluten.

A successful souring can be judged by a few signs as: Smell - should pleasantly remind of soured apples. Clearness - no signs of mold. Also, a slippery feel when gently rubbed between fingers (this slight viscous attribute probably works wonders for gluten sheets in the dough with all subsequent benefits from that).

The sandwich bread shown in the photos below was made using this mash with initial pH4.3, temp 103-108F, soured for 46 hours:

500g         water

150g         cracked rye malt

3.8g|1tsp  apple cider vinegar 5%

Savvas