Overview
Adding dairy products to bread dough has been done since times immemorial. This article looks at how they affect the dough and how best to use them to change your doughs in the ways you prefer.
When we add dairy products to dough it helps to think about it as adding four things, Water, Saturated Fat, Protein and Lactose. Lactose is a complex sugar found in milk and dairy products. We don't taste lactose as being sweet, so it doesn't convey a sweetness to the bread.
Adjusting the dough water is simple, just remember to subtract the amount of water in your added dairy product from the dough water in your recipe. There is a chart below to help you with the water content of the different dairy products.
In places this article get’s a little dense. If that’s not for you just skip forward because I then go on to give the same information in a plainer manner.
Bakers percentage are used in this article. If you want a refresher there is a section at the end.
Functional Ingredients
Dairy products are referred to as Functional Ingredients in bread baking. This group of ‘things we add’ to dough are functional insofar as they change the nature of the dough.
Inclusions, on the other hand don’t change the underlying chemistry of the dough, but add flavour, colour, changes in texture and more. Inclusions include seeds, dried fruit, herbs and spices, amongst other things. They don’t change the fundamental chemistry of the dough.
There are a couple of hundred functional ingredients used by commercial bakeries. Our home bakers list is much shorter and much more healthy too. They include: Scalded flour, ascorbic acid, animal fats (butter and lard), Eggs and egg yolks, lecithin, ascorbic acid, sugar, bean and pea flour, vegetable oil and vital wheat gluten. I will explore these and a few more in another article.
Fats in dairy products
Fats found in dairy products are saturated fats. They have a shortening effect on the gluten network. They literally make the gluten molecule networks shorter by cutting them up. This gives a less chewy bread which has a softer mouthfeel and better loaf volume. The greater volume comes from the reduced resistance to the dough rising from the weakened gluten structure.
Too much shortening makes the bread more cake like and the loaf volume diminishes too, because the bread cannot maintain its structure.
Fermentation produces CO2. The CO2 in a dough is held in bubbles in the dough. The walls of these bubbles are a lipid structure. Lipids are fats. They are effectively bubbles with complex lipid walls. As the CO2 is formed by fermentation it migrates into these bubbles (electro-chemical transportation) inflating the bubbles and so too the dough. When the bread goes into the oven the early heating makes the CO2 expand rapidly and this gives us our oven spring. The lipid bubble structures made by saturated fats are stronger than those that form if no saturated fat is added to the dough, or if unsaturated fats are used. This means they can hold more gas as they leak less. The CO2 that leaks out of the bubbles migrate out of the dough and it's lost.
The correct amount of saturated fats will enable our dough to rise more, giving us a lighter loaf. If too much fat is added, it coats the starches in fat hindering the amylase enzymes access to them. This means the amylase breaks less starch down into sugars for the yeast and the fermentation is hindered. When this happens we get a heavier bread. Brioche is an exception to this because the fat is in layers and not fully incorporated into the dough.
The sweet spot for dairy fat in bread is about 3% - 5% of the total flour weight. At this level the gas bubbles are at their maximum strength and there are no issues with lipids coating the starches. This will give the best loaf volume.
Adding fat to bread slows the rate at which the bread stales too. It does this by lowering the rate of water loss from the starch structure. As the starch looses water it crystallises. Hence stale bread is hard. Heating the bread through makes the starch re-hydrate, the crystallisation reverses and so the loaf is again fresh, but only for a short while.
Amounts to Use to give the dough 3% Saturated Fat Content.
Tip: If you make your own Soured Cream it can be frozen in weighed portions in a 1" cubed silicon ice tray. It freezes well and thaws quickly.
Other kinds of fat used in dough
Lard: Lard performs much like butter, but it doesn’t confer the fragrance and flavour given by butter.
Hydrolysed Vegetable Fats: These are also called Trans Fats. These perform in the same way as the saturated fats found in dairy products. However, the chemical processes that convert polyunsaturated vegetable fats into saturated fats makes mirror image molecular structures compared to those found naturally. The issue for us is that our bodies recognise them as fats, but we do not have the chemistry to break these mirror image fat molecules down. Our bodies produce cholesterol to break fats down. When they persist our bodies produce more and more cholesterol. The result is that these fats cause high cholesterol levels in the blood. Needless to say, they are a big factor in heart disease and more countries are restricting, or banning, their use in foods. I do not use them for this reason.
Vegetable oils These weaken the lipid walls making up the gas bubbles with the effect that they cannot hold as much CO2 and they leak more of it out into the atmosphere. Doughs made with vegetable oils tend toward a lower volume. Research has shown that if they are used at 2%-5% of the total flour weight in a dough, then this effect is not so marked. Used at 15% and above and the dough volume deceases rapidly. With flat breads such as pizzas, focaccia and fougasse there is not so much vertical dough weight to support and higher quantities can be used. Having said that 15% olive oil is rather a lot of oil and it gives an oily bread. Ordinarily 2%-5% is a good level to use in the dough. We can always pour more on top.
Using oils such as toasted sesame, walnut and olive oil can give the bread nice flavours.
There is no water in vegetable oils and they are not included in the dough hydration amount.
An interesting note on Casein: During digestion, casein releases opiates called casomorphins. Our dopamine receptors respond to these by triggering an addictive response. Yet dopamine makes us calm and relaxed. This is why milk helps us sleep.
Cheese is exceptionally high in casein. I like cheese.
How much Water and Saturated fat is in the dough?
When calculating the total water and fat levels in a dough we need to add up all of the different sources we have used in the dough. For example, if we have used butter, milk and eggs we need to add up the amount of fat and water each one adds to the dough, to ensure that we haven't altered the target hydration, or fat levels. Otherwise we are in danger of spoiling the bread by having too much.
An example calculation of fat levels in a dough
We are making a milk loaf made with 500g of flour with 70% hydration. We want to substitute 25% of that water with milk. We will add 1 egg yolk for it’s emulsifier properties and we want to add butter to get the fat content up into the 5% sweet spot. Emulsifiers make the dough less elastic and so enable the dough to rise more giving greater loaf volume.
The target hydration is 70%. We need to have a total of 370g of water from all of the ingredients.
Fat Calculation
The target level of fat is 5%. We are using 500g flour x 0.05 = 25g of fat is required
We are using 92.5g of milk which is 3.5% fat. 92.5 x 0.035 = 3.2g of fat from the milk
A medium egg Yolk weighs about 18g and it is 30% fat
So 18g x 0.3 = 5.4g Fat from the egg yolk
Total Fat from the Egg yolk and milk is 3.2g + 5.4g = 8.6g
The total saturated fat required in the recipe = 25g - fat from milk and egg yolk 8.6g = 16.4g fat still to be added.
Butter is 80% fat so multiply the amount of fat wanted by 1.25 (100/80). That is 16.4 x 1.25 20.5g butter required to give a total 25g of saturated fat.
You may well decide that it is not worth calculating this out. As long as you are not adding ingredients at their useable limits, I would agree. Unless you are doing recipe development where accuracy really does matter when it comes to repeatability.
A good trick is to make up a chart for butter, milk and egg yolks so that you can just look up the numbers.
The other way to go is a simple spread sheet, which is what I use.
Water Calculation
We want 70% hydration (water)
Total four weight 500g x Hydration 0.7 = 350g of water needed.
25% of the full fat milk. 350g x 0.25 = 92.5g Full Fat Milk
Full fat milk is 87% Water. So with 92.5g of milk we are adding 92.5g x 0.87 = 80.48g Water from the milk.
An Egg yolk is about 18g and it is 50% water. 18 x 0.5 = 9g water from the egg yolk
Total water from the egg yolk and milk = 9g + 80.48g = approx. 90g water
Water required = total water - water from the egg yolk and milk = 350g - 90g = 260g Water to be added to the dough.
Milk, Protein: Casein and Whey
The main proteins in milk are Casein and Whey. In full fat milk 80% of the protein is casein and 20% are whey proteins. Casein is what we are after for the soft mouthfeel. The whey, less so.
Whey Protein
Whey protein in reasonable quantities weakens the dough and so diminishes the volume of the loaf. However, the whey protein is only 0.9% of liquid whey, which is not enough to do so much harm. Overall whey is of little value to the baker as a functional addition to the dough.
Whey typically has high levels of lactose (milk sugars) 4.5%. This is much higher than the amount of whey found in milk. Whey will accelerate crust browning, See Lactose below.
N.B. Commercial bakeries use a lot of whey protein, but theirs is Acid Whey, they treat whey with Hydrochloric acid and then neutralise the acid afterwards. A very different product.
Whey proteins quite often ‘come along for the ride’ in dairy products and bread baking. Buttermilk with its casein is of much more use to us.
Casein
Casein gives the bread:
· A more uniform and fine soft crumb. Softer mouthfeel.
· Longer shelf life
· A lighter mouthfeel and slightly richer-tasting bread
· Slightly reduced loaf volume.
The above positive effects peak at about 1.1% Casein by flour weight. After that the dough becomes less stable, ferments more slowly, the gluten is weakened and the loaf volume decreases. A poorer bread is the result. The exception is if the milk is scalded and then we can exceed this amount without harming the dough.
The sweet spot of 1.0% Casein is the equivalent of replacing the water in the dough with:
35% Whole milk - If the Milk is scalded more can be used - see below.
53% Skimmed or low fat milk. If the Milk is scalded more can be used - see below.
35% Butter Milk. Scalding the Buttermilk changes its chemistry allowing more to be used See scalding below.
3.5% Skimmed Dried Milk will give the 1% Casein though more can be used. See scalding below.
6% Full Fat Dried Milk will give the 1% Casein though more can be used. See below.
29% Live Full Fat Yoghurt.
Soured Cream.
There are two types of soured cream in the shops. Chemically Soured Cream and Fermented Soured Cream. Both start off as Double, or Whipping Cream. The first is soured chemically and the flavour is not so great. Fermented Soured Cream has a wonderful flavour which is carried into the dough.
To make traditional butter the cream is first soured with a bacteria culture and then it is churned to make butter. It's very easy to make at home. Home made Soured Cream has a water content of 10% - 15%. Bought soured Cream has a water content of 63%. They add water to make it useable as a topping otherwise it would be too stiff.
Soured cream gives dough a tremendous flavour boost compared to butter from the shops which is not fermented. I highly recommend it's use instead of butter.
However, at 3% and above Saturated Fat content in the dough the crumb is markedly shortened. This is good for things like Burger Buns, English Muffins and Sandwich Breads.
2% gives less shortening, but still improves the mouthfeel and keeping qualities of the bread. I add saturated fat at 2% to my lean doughs such as Ciabatta and Baguettes to improve their shelf life at a slight cost of some shortening of the crumb.
Soured Cream cannot be added solely for it’s Casein as it’s fat content is too high. I use it instead of butter for the extra fermented flavour it gives.
Adding Soured Cream at 17% adds 3% Saturated Fat and 0.3% Casein to the dough.
Adding Soured Cream at 28% adds 5% Saturated Fat and 0.54% Casein to the dough. Adding Soured Cream at 56% adds 10% Saturated Fat and 1.04% Casein to the dough.
At 56% Soured Cream the crumb will be very short indeed because of the high fat level.
Focussing on Milk
An in depth study was conducted 2020 using full fat milk in a white dough. The researchers replaced the water in the dough with milk in differing amounts. They found that replacing 25% of the water with whole milk was the sweet spot. At this level the following characteristics were maximised:
· Increased dough elasticity leading to a finer and slightly denser crumb
· A softer mouthfeel
· Increased crust browning
· Improved water retention with the bread being moister and staling more slowly.
· Increased bread firmness, gumminess, chewiness and resilience.
Fresh milk. including pasteurised milk, does not work well in bread dough. It contains a protein called glutathione which weakens the gluten and gives a heavier loaf. Scalding the milk to 82.2C 180F denatures this protein and it is then no longer a problem. Fresh milk, including pasteurised milk should be scalded. Pro bakers use dried milk which does not require scalding.
Buttermilk
Buttermilk comes as two types. Buttermilk from making fermented butter and buttermilk from unfermented butter. Fermented Buttermilk is not at all common and it is likely to be marked on the label as ‘fermented’.
For our purposes there is little difference. The higher acidity of fermented buttermilk helps the yeast through increased dough acidity, strengthens the gluten and it confers slightly better flavour to the bread. In all other respects they are the same.
I have seen Buttermilk added as a direct substitute for all of the water in Soda bread (known as Scofa bread in Scotland). The acidity helps the baking soda to work. Soda bread is more like a cake, so the information given above regarding yeast breads does not apply. Having said that I have seen it added at 75% of the total water in Buttermilk Bread. I have never baked with it at that level.
Buttermilk raises the acidity of the dough and this helps the yeast fermentation and strengthens the gluten making the dough a little more elastic. The organic acids also react with other components found in fermenting dough to make more aroma, flavour, than would otherwise be the case.
Full Fat Yoghurt (Live)
This adds some fat, some casein and flavour. The Lactobacilli (LABs) will also add a little more flavour as well. However the LABs in Yoghurt are varieties which digest milk sugars, (Lactose) and they do not digest the sugars found in dough, unlike the LABs found in natural leavens (Sourdough).
Live yoghurt is slightly acidic. This increases the acidity of the dough. The increased acidity will improve yeast fermentation, assist the development of flavours and strengthen the gluten a little.
Plant Milks
Plant milks are nothing like dairy milk products. They have no casein and the fats in them are polyunsaturated the same as vegetable oils. They may well improve the nutritional value of a bread, but they will not have the same functional effects as dairy products.
Heat Treating Milk and Butter Milk
This is the game changer. Heat treating milk increases the loaf volume.
The milk is already heated in the pasteurising process. Pasteurising removes a lot of the bacteria, but it does not scald the milk.
Scalding requires the milk to be heated to a higher temperature to remove the glutathione which harms the loaf volume. It is also beneficial to do this for cakes and other baked goods that contain milk. However, cake recipes usually contain less milk, it’s often unnecessary to scald it.
At 82C 180F milk becomes scalded. To do this, heat the milk in a pan and keep stirring it as it is heated. when it reaches 82C 180F for just a second, and remove it from the heat. This is just below boiling point, and you should see some steam while small bubbles will form at the edge of the pan. If this temperature is exceeded, milk can produce an unpleasant flavour which we want to avoid.
Heat treating soured cream and yoghurt can be done by mixing them with some of the dough water to make them more liquid and then proceeding as above.
Heat treated milk can be used in quantities exceeding the 1% Casein recommendation above. Heat treated milk does not reduce the loaf volume. Yet the added crumb softness from the Casein remains is retained.
Why Dried Milk?
Commercial bakeries add milk as dried milk. Most dried milk is scalded in the drying process. They also use low fat dried milk as they prefer to adjust the fats in their doughs separately from the casein. Dried milk is very easy to use in home baking too as it requires no water adjustment and no scalding.
As with Scalded Milk Dried Milk does not reduce loaf volume if the 1% Casein is exceeded. The softer mouthfeel effect for the Casein remains.
Lactose
Lactose is the sugar found in milk. It doesn’t taste sweet to us, but it is a sugar nonetheless. Yeast is unable to ferment lactose, however the lactobacilli in natural leavens do ferment some of it.
If using a yeast only fermentation the lactose will persist in the dough and, like all sugars, it will lead to the crust browning a little faster and it will give the loaf more crust colour and a better flavour. To ensure the dough is baked through before the crust becomes too dark the oven should be set to a slightly lower temperature. Reducing the oven by 10C, 50F is generally about right, but ovens vary.
Bakers % and factors
This article uses bakers percent and factors.
Listing recipes in bakers percentage is really useful.
At a glance you can see if an ingredient is way off the mark. So many published recipes are either ill thought through or have typos. As soon as I am given a recipe I convert it to bakers percent. Something like 30% hydration, or 20% fat stands out like a sore thumb and it is then so easy to correct the figure to something that is workable.
Bakers percent of an ingredient is the weight of the item as a percentage of the total flour weight.
If I am baking with 500g of flour and need 80% hydration (water) 500 x (80 ÷ 100) = 500 x 0.8 = 400g of water.
80% of 'something' is the same as the weight of the 'something' x 0.8.
0.8 is called a factor.
So if you are working with bakers percentage just divide the percentage of the item required by 100 and multiply it by the weight of flour to get the amount of the item in the recipe.
There is a fuller article on how to use Bakers percent here:
Very interesting. Now I see why I use milk, and also use scalded milk in cakes. I thank you for all the hard work you put into this article!
21st July 2924
Fully revised with additions.