In the past order valtrex antiviral 1 gram drug buy valtrex online shop https://valtrexshop.com/ it was a common instruction in craft baking to give the rising dough a “knock back”. There were even different expressions for this process, and many times I have read in bakery books printed during the craft’s hey-day between the wars instructions like “after an hour give it a good knocking up….”. Knock down, knock up, de-gas – it was all much the same.
It was intended to help the dough along by knocking the gas out of it. After fermentation had proceeded for enough time for the dough to be gaseous and puffed up, it was presumed that fermentation would be suffering because the individual yeast cells would have become separated from their food (starch sugars) by the presence of the gas and alcohol that they themselves generated as they absorbed that sugar. It made good sense to knock a dough down so that such a violent disturbance of it would re-arrange the yeast cells in relation to their food, and the cells would be free to feed efficiently after the removal of superfluous gas that was literally getting in the way. It was further acknowledged that the stretching of the dough occurring in the pushing and folding exerted by the knock back process would be a healthy manipulation of the gluten that would leave it strengthened for the next gassing period. In this way the two key things of fermentation were being seen to: vigorous yeast activity ensuring gas production, and healthy strong gluten.
As flour became stronger in gluten and bakers shamelessly crept further into their dependence on chemical aids to fermentation, the discipline of a knock back being regarded as an integral part of dough fermentation began to wane. When I began baking in the ’70’s it had all but disappeared and I only knew about it by reading the old books.
Then there was a revival of it in the ’90’s driven mainly by American bakers who aspired to make the bubbly and gaseous breads of Italy and France. Their way was not to call it a knock back, but to use the term “fold”, both noun and verb.
Following the principles of the knock-back, the devotees of the fold do sing its praise for the twin benefits of invigorating the yeast and strengthening the gluten which will be rendered more elastic by the folding action. However, a critical difference is that the modern fold is performed rather earlier than the old-fashioned knock-back, and it is rare to find mention of this point, as well as the subtle but important benefit – folding enhances the random and large gas bubble that the baker seeks in these continental breads. If you make sure the fold is not done late, the folding action will trap gas rather than expel it. This gas trapping occurs because when the gluten is green (in an unripe state) it is tough enough to simply allow the gas bubbles to be folded into its overall bulk.
In contrast to a well staged early fold, if folding occurs late the riper gluten would be lower in elastic strength and its strands would easily part or tear, allowing gas to escape – which is exactly what happens at maturity when a puffy ripe dough is dumped on the work bench.
My conclusion about this topic is that I favour folding for those breads where I am aiming for the large gas bubble in the finished bread to be random in differing size and distribution. I include it in my method for such continental breads as pugliese, ciabatta, baguette, fougasse, sourdough wheat, etc. I wonder how many of my readers are already familiar with the fold, and on what bread types they prefer to do it?
I recommend a fold (or two, with a suitable space in-between), to be completed by around the half-way mark for what you perceive to be the expected bulk fermentation time.