Flour Fundamentals
Understanding Wheat, Milling and the Flour in the Bag
Flour seems like one of the simplest ingredients in the pantry. Take wheat, grind it into a powder, and you have flour. The more we have worked with Australian growers and flour millers, however, the more we have realised just how incomplete that picture is. Two bags can carry the same broad description and protein percentage yet absorb different amounts of water, develop differently during fermentation and produce quite different results. Flour begins long before the grain reaches a mill, and its behaviour depends on the grain, the season, the milling choices and what we ask it to do in the kitchen.
Why?
Because flour begins long before the grain reaches a mill.
The variety of wheat, where and how it was grown, the season it experienced, the characteristics of its protein and starch, the way it was cleaned and conditioned, the milling system, the amount of the grain retained in the flour and the decisions made by the miller all contribute to what eventually ends up in the bag.
So rather than asking simply whether a flour is stoneground or roller milled, or what its protein percentage is, it is more useful to ask:
What grain went in, what did the miller do with it, and what kind of flour were they trying to make?
That is what we are going to explore here.
It starts with the wheat
Wheat is not a single uniform ingredient.
There are thousands of wheat varieties, each with different characteristics. Some produce hard kernels and strong doughs suited to bread. Others are softer and better suited to cakes and biscuits. Some produce dough that is particularly elastic, while others are more extensible. Some mill readily into very white flour, while others are valued for flavour, colour or particular baking characteristics.
Australian wheat classification provides a good example of this.
Wheats are not classified simply according to protein percentage. Varieties are assessed for characteristics including milling performance, dough behaviour and end-use quality. Australian Prime Hard, Australian Hard, Australian Premium White and Australian Soft wheat, for example, are intended for different applications even though protein is one of the measurements used in describing them.
This distinction matters.
A flour containing 13% protein does not automatically behave like every other flour containing 13% protein.
Variety matters
Different varieties contain different combinations and characteristics of proteins, starches and other components inherited from the plant.
Modern bread wheat has been bred over generations for particular agricultural and processing qualities. Older varieties may have been selected under quite different farming and milling conditions.
Then there are related wheat species such as spelt, emmer and khorasan, whose grain and dough characteristics can be different again.
This is one reason we have become increasingly interested in knowing the actual variety behind our flour rather than simply knowing that it is "Australian wheat".
What about heritage and ancient wheats?
Terms such as ancient grain and heritage wheat are useful, but they can also oversimplify a complicated story.
Ancient wheats generally refer to older wheat species and grain types such as einkorn, emmer, spelt and khorasan.
"Heritage", however, does not have one universally accepted scientific definition. We tend to use it more practically to describe older named wheat varieties that pre-date much of modern wheat breeding and remain connected to a particular historical period or agricultural tradition.
The important thing for us is not that older automatically means better. It is that different genetics produce different grain. An older variety may have a distinctive flavour, dough character or relationship with a particular growing environment. A modern wheat may possess exceptional disease resistance, yield stability and baking performance. Understanding what we are working with is much more useful than reducing wheat to a simple old-versus-new argument.
The season and the place matter too
Genetics only gives us part of the picture.
One of the themes we keep returning to in our articles about grain is the relationship between genetics, environment and place.
A wheat variety carries its genetic potential, but the grain harvested from it is also the product of where and how that plant grew.
Rainfall, temperature, soil type, available nutrients, moisture stress, disease pressure and the timing of seasonal events can all influence the grain that eventually reaches the mill.
The same wheat variety grown in two different districts may not produce identical grain. Even the same grower planting the same variety in the same paddock can harvest grain with somewhat different characteristics from one season to the next.
This can affect things a miller or baker actually notices: protein expression, kernel size and hardness, flour yield, water absorption, dough strength and, potentially, flavour.
We have discussed this relationship between grain and place throughout our articles on khorasan, emmer, rye, spelt and wheat. It can be particularly noticeable when working with older or less standardised varieties, but the principle applies to modern wheat as well.
The variety sets the possibilities. The environment helps determine how those possibilities are expressed.
This can become even more apparent in organic grain production. Organic growers still actively manage soil fertility and crop nutrition, but they have fewer rapid corrective levers available during the growing season. They cannot simply respond to conditions by applying highly soluble synthetic nitrogen fertiliser late in the crop to influence grain protein. That places greater emphasis on what has happened beforehand: fertility built in the soil, crop rotations and legumes, the timing and availability of nutrients, stored soil moisture, rainfall and the conditions the crop encounters as it develops.
In that sense, organic grain can reveal the interaction between variety, soil, season and farming system particularly clearly. The genetics still set the possibilities, but the environment and the way the farm has been managed play a substantial role in determining how those possibilities are expressed in the harvested grain.
Large flour mills manage this natural variability through grain testing, segregation and blending. Wheat from different farms, districts, varieties or harvests can be combined to produce flour that meets a consistent specification.
That consistency is extremely useful, particularly for commercial bakers.
But when we work with grain from an individual grower, variety or harvest, we see another side of flour.
The differences between seasons do not necessarily need to be regarded as faults that must be eliminated. They can also tell us something about the grain, the farm and the conditions under which it grew.
Knowing the variety is useful.
Knowing the grower and where it was grown adds another layer.
Knowing the season begins to complete the picture.
Baker’s Note: Same variety, different season
While more apparent with single origin flours, don’t be surprised if a familiar flour feels slightly different after a new harvest. The same wheat variety can absorb more or less water, develop differently and produce a slightly different flavour depending on the conditions in which it was grown.
Start with your usual recipe, then adjust by feel
What is inside a wheat kernel?
Before talking about milling, it helps to understand what the miller is working with.
A wheat kernel is broadly made up of three main components.
Bran
The bran forms the outer layers of the kernel.
It contains much of the grain's fibre and a considerable proportion of its minerals and other compounds. Bran contributes flavour, colour and texture to wholegrain flour.
From a baker's perspective, bran also matters physically. Bran particles absorb water and can interrupt the developing gluten network, which is one reason wholegrain dough often requires more water and behaves differently from dough made with highly refined white flour.
Endosperm
The endosperm makes up most of the wheat kernel.
It consists predominantly of starch, along with proteins including those that eventually form gluten when flour is mixed with water.
Most white wheat flour is produced primarily from the endosperm.
Importantly, the endosperm itself is not completely uniform. Its composition changes as we move from the centre of the kernel toward the outer layers.
Milling therefore isn't simply a question of separating "white flour" from "bran". Different parts of the endosperm can produce flour streams with different characteristics.
That becomes particularly important in roller milling.
Germ
The germ is the embryo from which a new wheat plant could grow. It contains oils along with vitamins and other nutrients. Those oils contribute some of the flavour of wholegrain flour but also make flour containing the germ more susceptible to oxidation during storage.
That is one reason wholegrain flour generally has a shorter useful storage life than highly refined white flour. A wheat kernel also has a deep longitudinal crease. Part of the outer layers fold into it, which helps explain why a roller mill opens and separates the grain through repeated passages rather than one simple crush.
Common bread wheat is generally free-threshing, while hulled wheats such as spelt and emmer require an additional dehulling stage before milling.
What does a flour mill actually do?
At its simplest, milling reduces grain into smaller particles. But producing good flour involves much more than making wheat small. A miller is trying to control which parts of the grain end up in which flour, how finely they are milled and how the resulting flour behaves.
There are many mill designs, but most wheat flour encountered by Australian bakers will have been produced using either roller milling or stone milling.
They are different approaches, but we don't think one should automatically be regarded as superior to the other.
They are tools.
What matters is the grain being milled, how the mill is operated and what the miller is trying to produce.
Roller milling
A roller mill progressively opens the kernel, separates pieces of endosperm from bran, sifts the material and reduces selected particles into flour. This creates several flour streams that the miller can combine to achieve particular characteristics.
Stone milling
In stone milling, the grain passes between two stones and is milled together before the meal is used whole or sifted. The stone, its dressing, feed rate, milling speed, grain moisture, particle size and sifting all influence the result.
Neither system guarantees good or bad flour. The useful questions concern the grain, how it was prepared, how much of it remains in the flour, how finely it was milled and what the miller was trying to achieve.
When flour is hydrated and mixed, folded or kneaded, gliadins and glutenins begin interacting to form gluten. Gliadins contribute more to extensibility, while glutenins contribute more to elasticity and strength. The network develops according to the flour, water, time, temperature and handling.
Water also hydrates starch, bran and fibre. Higher-extraction and wholegrain flours usually need more because these components absorb significant amounts of it. A familiar hydration percentage can therefore feel very different when the flour changes.
The right flour is suited to the job
Bread generally needs enough strength to retain gas, but the strongest flour is not automatically the best. Pizza needs extensibility as well as strength. Cakes, biscuits and pastry usually benefit from controlling gluten development, while sauces and gravies rely principally on starch for thickening.
Wholegrain flour retains bran, germ and endosperm in roughly the proportions present in the grain. Bran competes for water and interrupts the gluten network, so wholegrain dough often benefits from more hydration and time.
Rather than thinking that high protein means good flour, it is more useful to think that the right flour is the flour suited to the job.
Why flour changes from harvest to harvest
One lesson that comes from working directly with agricultural products is that consistency has limits.
- A factory can manufacture identical stainless-steel bolts every year.
- A wheat plant cannot manufacture identical grain every year.
- The same grower can plant the same variety in the same paddock and still experience a different rainfall pattern, temperature, soil moisture and growing season.
- Large flour mills manage this variability through testing, segregation and deliberate grain selection.
- They may combine different parcels into a grist before milling and then combine selected flour streams afterwards.
Consistency, in other words, is often something the miller creates from naturally variable agricultural inputs.
That consistency can be extremely valuable, particularly for commercial bakeries.
But there is another way to look at natural variation. Instead of assuming every difference must be hidden, we can also try to understand it.
- Wine drinkers are comfortable with the idea that vintage matters.
- Coffee drinkers increasingly understand origin, variety and processing.
Flour can be understood in much the same way. Not every variation is desirable, as flour still needs to perform. But variation is not automatically a defect when the product begins with a crop.
Flour is both grown and made
Before there is flour, there is a wheat variety, a grower, a soil, a farming system and a season. A miller then makes choices about grain, cleaning, conditioning, grinding, separation, extraction, particle size and blending. In the kitchen, water, time, temperature, ingredients and technique complete the story. Flour is both an agricultural product and a milled product, and neither side tells us everything by itself.
Stoneground is not automatically better than roller milled. Wholegrain is not right for every purpose. Higher protein does not automatically mean better flour, lower ash does not mean higher quality, and freshly milled does not automatically mean better baking performance. These are characteristics to understand rather than rankings to apply.
The useful question is not simply which flour is best. It is what grain the flour was made from, where and how it was grown, how it was milled, how it behaves and what it is good at.
Glossary
Ash
A laboratory measure of the mineral material remaining after a flour sample is burned. Because minerals are more concentrated toward the outer parts of the wheat kernel, ash can help indicate how refined a flour is.
Bran
The outer layers of the wheat kernel. Bran contains much of the grain’s fibre and minerals and also affects water absorption and gluten development.
Endosperm
The largest part of the wheat kernel, made mostly of starch with proteins that contribute to gluten formation. Most white flour comes primarily from the endosperm.
Extraction rate
The proportion of the original grain that becomes flour. Higher-extraction flour generally contains more of the outer parts of the kernel, while lower-extraction flour is more refined.
Germ
The embryo of the wheat kernel. It contains oils, vitamins and other nutrients and contributes to the flavour and shorter storage life of wholegrain flour.
Grist
A selected blend of wheat parcels or varieties prepared for milling. Millers may create a grist to achieve particular characteristics in the finished flour.
Heritage wheat
A practical term often used for older named wheat varieties associated with earlier periods of farming and breeding. It does not have one universally accepted scientific definition.
Protein percentage
The proportion of protein in the flour. It can be a useful guide to potential gluten development, but does not by itself describe dough strength, extensibility or overall baking performance.
Variety
A particular genetically distinct type of wheat. Different varieties can differ in kernel hardness, protein characteristics, flavour, milling performance and baking behaviour.
Wholegrain flour
Flour that retains the bran, germ and endosperm in approximately the proportions found in the original grain.
