Bread Matters (11 page)

Apart from food in the form of sugars, yeast needs water and warmth. The optimal temperature for yeast fermentation is 25-28°C. At this temperature, water feels slightly warm to the hand. Above about 46°C and below about 10°C yeast works very slowly. It is killed at around 60°C. It follows that dough temperature and fermentation speed are closely connected – a fact that can be used both to produce better bread and to fit the whole process into the life of the home baker. It also follows that you may need to adjust yeast quantity and dough temperature to reflect the changing seasons.

Fresh yeast

This should be stored at around 5°C – the temperature of a domestic refrigerator on a fairly high setting – and used within a couple of weeks. Its gassing power progressively reduces as it gets older. If you store fresh yeast at 15°C for two weeks, it will take twice as long to prove your bread. As it ages, fresh yeast becomes crumbly and may form dark patches on its surface. It will still work in this condition, but it may lack gassing power and may also introduce by-products into the dough that have a negative effect on the strength of the gluten network
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. As a last resort, fresh yeast can be frozen, but it turns to a runny mess on defrosting and loses a significant amount of its efficacy. Yeast is best stored in its dried form.

Dried yeast

There are two kinds of dried yeast – the traditional ‘active dried’ yeast, in the form of small granules, and ‘instant’ or ‘fast-action’ yeast, which looks more like fine iron filings. The latter may come already mixed with additives such as vitamin C and ‘rehydration agent’. Quite why this form of yeast needs something to help it get wet (other than water) is doomed to remain a mystery for as long as the manufacturers follow that irritating food industry habit of adding ingredients with opaque or meaningless descriptions and no indication of any valid reason for their inclusion. Presumably it is a belt-and-braces measure to ensure that this kind of yeast lives up to its ‘instant’ name, enabling it to be chucked into the dough mix without prior dispersal in water. In fact, both fresh and traditional granular dried yeast could also be added straight to the dough mix.

Fast-action yeast is more concentrated than traditional dried yeast and both are, weight for weight, more concentrated than fresh yeast. The recipes in this book use fresh yeast but will work equally well with either of the dried versions. The rule of thumb when converting a recipe for the kind of yeast you have available is:

10g fresh yeast = 5g traditional ‘active dried’ yeast = 3g ‘fast-action’ yeast

I prefer to dissolve all yeast, including the ‘fast-action’ variety, in water prior to mixing, simply to ensure its complete dispersal throughout the dough. If granular dried yeast is added without being dissolved, some of it may fail to disperse if you don’t knead thoroughly, and can show up as little brown specks in a dough that may not rise as well as it should. A further reason for dissolving dried yeast in water before adding it to the flour is as a check on its efficacy. If it has been hanging around in a not-very-airtight tub or opened sachet for a while, it may not be in good condition. Sprinkled into some warm water (30°C), or mixed with a little flour and water into a sponge or ‘ferment’, it should start to work in a few minutes. If it doesn’t show any signs of life after half an hour, you should consider it moribund and start again with a new source; at least you won’t have wasted a whole dough and all the effort expended in kneading it.

Organic yeast

It may come as something of a surprise to discover that the yeast used in organic bread is not necessarily organic. When organic food production in the European Union was given a legal definition in 1992, yeast was treated, like salt, as a ‘non-agricultural’ ingredient, and therefore fell outside the scope of the legislation. In any case, at that time there was no commercially available organic yeast. However, unlike salt, yeast production has clear connections with agriculture. Conventional, non-organic yeast is produced primarily on a substrate of non-organic sugar molasses, whereas organic yeast grows in a broth made with water and organically grown wheat flour. So for every ton of yeast produced, an acreage of land has been cultivated to produce either non-organic sugar (usually beet) or organic wheat, with all the attendant chemical fertilisers, herbicides and pesticides that are, or are not, used under the two systems. That’s not all. There are huge differences in manufacturing method, with environmental implications. Non-organic yeast uses ammonia and ammonium salts as a yeast food, sulphuric acid and caustic soda as acidity regulators and cleansers, synthetic vitamins and mineral salts as processing aids, and synthetic anti-foaming agents to control the fermentation froth. As a result, every three kilos of non-organic yeast generate a kilo of polluted waste water whose disposal creates an environmental problem. By contrast, organic yeast production uses no yeast foods other than brewer’s yeast, no acidity regulators and only a little organic sunflower oil to control foaming. It produces no waste water because the liquid that is squeezed out of the yeast at the end of the process is used as raw material for other products, such as drinks
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.

Organic yeast is produced in commercial quantities in a former brewery in southern Germany (I have seen the process myself) and is being used by many certified organic bakeries on the Continent. Until recently, distribution to the UK has been difficult, but both fresh and dried versions of the yeast are now available in specialist shops. The Soil Association has developed a standard for the use of organic yeast in baking and, despite an initially dismissive attitude by the UK yeast industry and the big bakers, it is likely that, in time, it will become the norm for organic bread, in line with both agricultural logic and consumer expectations.

Coeliacs and people with wheat allergies may be concerned that organic yeast is grown on a substrate of wheat flour. However, the manufacturer (Agrano) says that the wheat protein is consumed (hydrolysed) by enzymes during the process and that no gluten has been found in the finished organic yeast using the ELISA test (the industry-standard way of testing for gluten). Agrano adds that it cannot exclude the possibility that traces of gluten may exist at levels below the current limits of detection.

Sugar

Many recipes call for sugar to be added to the water in which the yeast is dissolved. It is true that ‘sugar’ is a yeast food, but only up to a point. When yeast has an adequate supply of sugar (in the form of maltose) derived from the flour, adding extra sucrose will not make it produce more gas. Indeed, when sugar is added at more than 5 per cent of the flour weight, it begins to have a detrimental effect on yeast activity. This explains why considerably more yeast is needed in a sugar-enriched bun dough than in a plain bread dough.

Sugar does a variety of things in the baking process, apart from its obvious sweetening effect. As a yeast stimulant in a dough to which sugar would not otherwise be added, it seems to me to be of dubious value. Modern yeast strains are bred to be extremely vigorous and probably don’t need the sweet kick up the pants that may have been called for in days gone by. In
The English Bread Book
(1857), Eliza Acton has recipes using both liquid brewer’s yeast and compressed ‘German’ yeast, which was becoming available in towns in the middle of the nineteenth century and which she noted was considerably more vigorous than the alternatives. She suggests adding a little sugar only to ‘freshen or aid the fermentation of stale yeast’ and doesn’t include it routinely in her basic recipes. In an age when we are advised to reduce sugar consumption, omitting it from our everyday bread combines sensible practice with a modest concession to dietary correctness.

Malt

I have already referred in various places to the alpha-amylase enzymes that are present in, and often also added to, breadmaking flours. Alpha-amylase is also known as dextrinogenic amylase, or diastase, and its function is to begin the process (completed by the enzyme beta-amylase) of converting starch to maltose, a simple sugar that can be metabolised by yeast. This process is sometimes referred to as diastatic activity, and it is of interest to the baker because if it is not happening very much (due to insufficient diastase), yeast fermentation and the consequent expansion of the dough will be limited. Conversely, excessive diastatic activity can make the dough gummy, leading to the partial or complete collapse of the structure.

Malt flour can be added to dough in order to improve the conversion of starch to sugars. You might wish to do this if your normal flour seems to be giving a consistently pale crust, suggesting that there are insufficient sugars available to caramelise at the baking stage. Malt flour can be particularly useful in long-process doughs (including sourdoughs), where the length of the fermentation allows the yeasts to use up all the sugars. In the above cases, a very small amount (perhaps as little as 0.1 per cent of the flour weight) of diastatic malt flour is what you need. Non-diastatic malt flour has been heat treated to deactivate the enzymes and so has no effect on fermentation, but it does contribute a malty flavour. The same applies to liquid malt extracts: the ones you will find in wholefood shops are normally non-diastatic, while enzyme-active ones can be had from home-brewing suppliers.

Malt flour is not easy to obtain in its pure form, so the most practical solution for a home baker looking for the benefits of malt in a dough is to use a certain amount of a proprietary malted flour – the type that usually has bits of malted grain in it. Otherwise, try a home-brewing supplier or one of the specialist flour suppliers listed on pages 351-352.

Salt

Salt (sodium chloride) plays an important part in breadmaking, but don’t believe those who say that it is impossible to make bread without it.

Salt performs the following functions in breadmaking:

• It affects flavour: many people in the UK (especially north of the border) dislike bread with low levels of salt. However, as with sugar in tea, it doesn’t take long to get used to its absence or reduction.
  
• It has a strengthening effect on the gluten.
  
• It acts as a preservative and so extends the mould-free life of the loaf; it is also hygroscopic (it attracts water), so it may draw moisture into the loaf from the environment.
  
• It affects crust colour: bread with excessive salt can take on a slightly reddish hue – what bakers traditionally described as ‘foxy’. If your bread has an unexpectedly pale crust, this may be a sign that you forgot the salt.
  

Salt inhibits yeast activity, and care should be taken to avoid direct contact between the two before mixing the dough. Once the salt is dissolved in water and is evenly spread throughout the dough, its negative effect on the yeast is minimised and its gluten-strengthening action can begin.

Sea salt, especially the coarse flaked varieties from Anglesey or the Guérande in France, retains a wider spectrum of minerals, including valuable iodine, than industrially processed rock salt. Avoid anything with ‘anti-caking agent’ in it. This is designed to make salt flow freely through automatic machines into processed food mixes. At home, if damp does get into your salt and make it a bit lumpy, it is not the hardest task in the world to break it up again.

With the current focus on reducing sodium in the diet in an attempt to limit heart attacks and strokes, various alternatives have appeared, usually based on potassium chloride. One that we used a great deal in the bakery is from a natural under-sea source in Iceland (see page 352): I like the fact that geo-thermal energy is used to evaporate it. Be aware, though, that potassium-based salt has to be used judiciously, otherwise it can impart a bitter taste to baked products.

Fats and oils

It is quite possible to make bread without any added fat or oil. Indeed, from a nutritional perspective, it is probably desirable to do so, partly because most of us already consume excessive amounts of fat and partly because it is known that heating even ‘good’ fats like olive oil beyond a certain point produces some harmful compounds. Gastronomically, there is clearly an honourable place for breads and buns enriched with fat. But, other things being equal, I would always prefer to consume any fat on my bread rather than in it. Much of the flavour of olive oil, for instance, is lost if it is baked into a ciabatta dough. Dipping freshly baked bread into a dish of murky green virgin oil is quite another matter.

If you add a modest amount of fat to an ordinary bread dough – not an ‘enriched’ one like a lardy cake or a brioche – it may have a small effect on keeping quality, but the main reason for including it is to improve gas retention in the dough and hence loaf volume. However, it is important to note that dough volume will be enhanced only by solid fats, not by liquid oils. The latter have a slightly depressing effect on volume.

Hydrogenated fat

Passing hydrogen gas through liquid oil has the effect of making it hard at room temperature. But it also has the undesirable effect of creating so-called trans-fatty acids, which the body cannot metabolise and which have been implicated in raised blood cholesterol levels. This means that the many margarines and spreads that include hydrogenated or partially hydrogenated fat should be avoided.

Hard fat

There is no avoiding the fact that fats that are hard at room temperature, such as butter and lard, are likely to have a high saturated fat content. But they do have the advantage of giving extra volume to bread, something that neither liquid oils nor semi-hard ‘spreads’ do.

The cereal chemists say that strong (high-protein) white flours require more fat than weaker ones and wholemeal flours more still. If you are going to experiment with additions of fat, the rule of thumb is that an addition of about 5g fat per kilo of flour will give maximum loaf volume, with rather more needed for wholemeal breads.