The archetypal image of a baker working all night so that there would be fresh loaves for the morning put many off entering baking as a profession. In France, twice daily bakings were the norm so that a second fresh baguette could be purchased on the way home. This level of turnover once paid the bills, but the Chorleywood Bread-making Process, developed in 1961, mechanised bread-making primarily with high speed mixing, but also with greater amounts of yeast and higher temperatures. It cut the bulk fermentation time from three hours to about as many minutes with the result that bread can now be baked continuously throughout the day (or night). It is hard for a traditional baker to compete financially with this mass production.
What of the home baker? Similar “advances” have been made to help them. The Chorleywood process has been adapted for home bread makers. These may not have the same high speed mixing ability, but with the aid of fast-acting yeasts the cook’s involvement in the process now requires little more than tipping in the ingredients.
What affect does cutting fermentation have on the end loaf? I think of gluten (the protein in flour that enables it to stretch as the dough rises) as being like bubble gum and during the fermentation process it will be partially “digested” making its final digestion by us much easier. When you cut this stage out, people often report a bloated feeling after eating bread. The glycaemic value is lowered by this fermentation process, meaning that the body absorbs the energy over a longer period of time. The bread will have a crisper crust and a chewier crumb and also be likely to stale less quickly.
In Fare Exchange, written in 1963, Dorothy Allen-Gray commented…
“Unless you have experimented you cannot realise the difference in the flavour, volume, tenderness and texture between a bread dough allowed to rise slowly and gently and a dough quickened by the use of too much yeast or heat”.
Dorothy Allen-Gray was of course writing in the very early days following the introduction of the Chorleywood Bread-making Process and since then even more has been understood about its implications. She refers to the use of too much yeast, and in addition to the advantages of long fermentation mentioned above, there are additional reasons for not wanting to use more yeast than is absolutely necessary. In the past the main reason was cost, but yeast is now very cheaply grown on molasses so that cost is no longer the issue. However, the by-products of compressed yeast production are not very environmentally friendly, and in fact there is no commercial yeast produced in this country that is certified organic, although you may be able to buy some imported from Germany. Too much yeast can also upset the natural balance of bacteria within the gut. How much is too much? Well, you do not need to increase yeast proportionate to the amount of dough you are trying to raise, but as a rough rule of thumb fresh yeast at a proportion of 1% to the amount of flour would be fine in a plain bread dough (enriched doughs need more), i.e. 10 grammes of fresh yeast to 1kg of flour. It is not uncommon to find bakers using three times this amount, which is definitely too much.
In English Bread and Yeast Cookery, Elizabeth David puts forward the practical advantages of long fermentation for the cook:
“ To me it seems both convenient and practical to give bread dough a long fermentation. Rather like meat steeping in a marinade it is looking after itself while you are asleep or busy with other jobs. What could be less troublesome?”
I find it especially convenient to ferment dough overnight if I want to eat the results sometime in the morning. For that reason alone I would advocate an overnight fermentation for this month’s Hot Cross Buns recipe, although as Elizabeth David pointed out …”this method for rich cake and fruit bread is against every accepted rule” even though it was a rule she too found convenient to break.
Why should it be an exception to use long fermentation for enriched, sweetened doughs I wonder? Initially these yeasted cakes were made with leftover dough from the main bread making. As fats and spices make it harder for the yeast to work (although sugar boosts its rate of action) I would have expected fermentation of enriched dough to have taken longer. If the dough is made specifically for a sweet cake it is usual for a greater proportion of yeast to be used to counteract the added fats and spices. After about 5 hours fermentation it is true that some wild yeasts will develop, which give a slightly sour note that may not have been thought desirable in sweet breads. However, any sourness after this time is very slight.
There is another factor in favour of long fermentation for enriched doughs – they tend to be more difficult to knead. Kneading encourages the protein molecules to bind together to form a web of gluten. In slow fermentation the molecules would eventually find one another, the process being easier the wetter the mixture. In The Handmade Loaf Master Baker Dan Lepard describes how he stumbled across this by accident when he was responsible for making the bread in a busy restaurant kitchen. He was frequently interrupted to perform some more immediate task but found on returning to the bread dough that it was as if someone had performed the kneading in his absence. Eventually he incorporated these breaks into his technique – deliberately mixing flour and water to begin with and then leaving them for a period of at least half an hour before adding the yeast sponge. Short periods of kneading, sufficient merely to combine the ingredients, were interspersed with longer periods of rest so that the total kneading was minimal. I have used this method myself ever since reading about it, and taught it in my cookery classes, where it has been especially valued by people who, through age or illness, find kneading difficult.
Any existing recipe can easily be adapted to slow fermentation. The components that affect the speed of fermentation are yeast and temperature, so it is just a matter of adjusting these. Compressed yeast appears to have become more “efficient” over the years so that smaller amounts are required than stated in older recipes. It has become more difficult to buy fresh yeast nowadays and the old rule of thumb used to be that if you substituted dried only half the amount was needed. However even the dried yeast has changed as the vast majority of what is available was designed for use in bread machines. These contain one or more of the following to make them faster acting: hydrating agent, ascorbic acid, alpha amylase. There is only one traditional dried yeast sold now (made by Allinsons) and personally this is the only one I would use, but if you have to use anything else I would halve the quantity again to get a slower fermentation. All bakers agree that fresh yeast produces better results than dried, but a small amount, left to ferment overnight so that the yeasts multiply, is acceptable.
The main techniques used in long fermentation fall into the following categories:
- Cool Temperature
This alone can be sufficient to ensure fermentation is slow. Some bakers prepare their dough and leave it in a refrigerator overnight. The technique is however usually combined with a reduction of about half the yeast.
- Sponge and Dough
This is the most popular method. Half the normal amount of yeast, together with half of the flour and somewhere between half and all of the water, are mixed together and left at room temperature overnight (if all of the water is used the sponge will be quite wet). During the night the yeast will multiply and some wild yeast (lactobacilli) will develop. In the morning the sponge is added to the remaining flour, water and salt for a second fermentation, which will be shorter than had all the ingredients been fermented together (two hours is normally sufficient at a warm room temperature).
- Wild Yeast
Wild yeast is naturally much slower acting than commercial compressed yeast. It does have a slightly sour flavour (hence the name Sourdough) and produces a much chewier crumb. Neither of these attributes are usually desirable in sweet doughs although there are exceptions, for example a traditionally made Panettone would be made with wild yeast, the big benefit being that the sour lactobacilli kill bacteria making the enriched dough last for a long time without the need for artificial preservatives.
Developing a wild yeast starter is a lengthy, somewhat hit and miss affair, but once you have this it is easy to keep going and always to hand. Bread made with wild yeast has an even lower glycaemic value than overnight doughs made with commercial yeast too.
To experience the benefits of long fermentation yourself this month’s recipes, including delicious Hot Cross Buns, are based on the Sponge and Dough technique.