Some Principles and Methods.
The first thing to be aware of with rye baking is that it is completely different to baking a wheat loaf. The chemistry is different and different methods are required.
The second thing is that breads, using more than 50% rye flour are much easier to make than a wheat flour bread.
By merely applying good practice and a little knowledge it is much easier to bake a five star rye bread than it is to bake one with a wheat based dough.
Some recipes contain both wheat and Rye. Jeffrey Hamelman has a break point with doughs which are made up of 50% rye flour or more he recommends switching to rye baking methods. Under 50% rye he recommends treating the dough more like a wheat dough.
I would put a caveat on that and say that for doughs containing more than 20% rye flour, methods like retarding the dough and autolysis should be avoided, because the more time the dough is fermenting the more time the rye flour's high levels of enzymes have to cause damage to the dough's structure.
Rye grain is low in glutenin, the precursor of gluten and so it is unable to develop a gluten structure to trap the CO2. It is the gluten in a wheat bread which traps the CO2 and enables the dough to rise. Instead, Rye is high in pentosans, complex sugars, that combine with the starches to form a pentosan-starch gel which is able to hold the CO2 from fermentation and so allow rye dough to rise. (Pentosan sugars are referred to as arabinoxylans in bread biochemistry). In commercial baking these pentosans are sometimes added to wheat doughs to increase water absorption and slow down staling. Rye is the only grain able to develop these starch gels.
Rye flour also contains high levels of amylases, a group of enzymes which break down starches into sugars. By converting too much starch into sugars the amylase enzymes stop this pentosan-starch gel from being able to form properly. This is called 'starch attack'. The result is a heavy gummy bread. Long fermentation times give the amylases more time to damage the starches. For this reason long fermentation times and cold fermentation are not recommended.
Another troublesome enzyme found in high levels in Rye flour are the pentosan group. These literally break the gluten bonds in the dough. Rye flour has very little glutenin so this is not a problem in 100% rye doughs. However, if we are using some wheat flour to get a more open bread structure they can undo our careful plans for a lighter bread.
The methods used for baking with rye must control both the amylase and pentosan enzymes. There are two ways of doing this. Firstly, and a less effective method, is to ferment the dough quickly and get it into the oven before the enzymes do too much damage. It gets worse, the amylase enzymes are active up to 80C and their activity spikes in the early stages of baking. So even in the oven they are wreaking havoc on the dough until the dough temperature reaches 80C. So starting a rye dough in a hot oven and then dropping the temperature after some 10-15 minutes is good practice. This is perhaps suitable for doughs with 20%-50% rye flour. I would not use it for doughs with more rye than that.
The second defensive method is to create an acidic dough. The acidity inhibits the amylase enzyme activity. Simple inoculation with yeast, or using a yeast preferment does not produce sufficient acidity. Yeast produces acetic acid, the same acid found in vinegar. It is not a pleasant flavour in bread. A natural leaven (a.k.a. Sourdough) contains Lactobacilli. These produce lactic acid which is pleasant to the taste in a rye bread. Rye bakers of old used a long fermented rye leaven which becomes very acidic. This is easily made by fermenting a natural rye leaven in a warm place for 16-24 hours. For those who want to take this process further see, 'Three stage sour rye leaven', the 'Detmolder Process' and the 'CLAS' method. I cover the easier and more commonly used two stage sour rye leaven below.
These acids inhibit the both the damaging pentosan enzymes and the amylase activity and enable us to produce rye breads with better crumb structures. The lactic acid flavours also compliment the rye flavours more so than in wheat breads.
Another difference between rye and wheat is that of the effects of the bran on the dough. Bran, in wheat doughs, has the effect of interfering with the gluten formation, which allows some CO2 to escape giving us a heavier loaf. This is not the case with rye doughs. The bran does not damage the gel formation and being much lighter than the gels it actually helps form a lighter loaf.
Other things which work in a similar manner are the use of a soaked seeds, or adding very coarse whole rye soaker (think kibbled wheat or steel cut oats). These make soft areas in the finished bread and give an overall mouth feel of a softer crumb.
Autolysis is never used in rye baking. It is a technique to develop gluten in white breads and as we have seen with rye bread we are not making use of that at all. Autolysis will also create the perfect window for amylase starch attack and pentosan damage.
Temperature
As we increase the temperature of the fermenting dough the yeast and LAB activity increases as well, but at different rates. If the temperature is increased beyond the peak activity temperature their activity decreases again until the temperature reaches their death point.
Peak yeast activity is reached at about 29C-30C.
Peak LAB activity is about 34C.
Over 30C Yeast activity starts declining sharply.
At 40C all LAB activity has ceased.
Between about 20C to 26C their activity levels are about the same. This is the optimum window for fermenting wheat doughs.
Going up to 28C is still peak yeast activity, but the LAB activity is raised even further and this will increase the finished loafs sourdough acidity. Which is a good thing.
Armed with this information we can see that fermenting at 29C-30C will increase the doughs acidity at a faster rate whilst the Yeast activity has plateaued and cannot it increase further. (see the graph below).
This is useful for making acidic rye preferments to add to the rye dough at the mixing stage so that the dough starts off as an acidic one which inhibits amylase activity. When this is done it is common to add some instant yeast to make up for the lack of yeast in the natural leaven. Add instant yeast at 0.0063% or, one level teaspoon per 500g of flour. This is the standard inoculation rate for wheat breads too.
Because we don’t want to extend fermentation times and encourage starch attack 28C-29C is the ideal dough fermentation temperature for rye breads.
These recommended temperatures are not written in stone. Skilled rye bakers step outside of these from time to time to develop particular crumb and flavour outcomes.
Stanley Ginsberg who wrote ‘The Rye Baker’ (The best book I have seen for rye bread in the English language), most often ferments his doughs at room temperature which for him varies from 20C to 25C depending on the season. He does, however, use a two stage Sour Rye natural leaven. (See below for instructions).
Types of Rye Flour
Like all flours the the rye flavour is mostly in the bran and germ and not the white endosperm in the centre of the kernel. The endosperm is that part which when milled makes white flour.
In the U.K there is a simple choice of rye flours. We have light rye flour (also called White Rye flour) which has had most of the Bran and all of the germ removed. I find it severely lacks flavour. There is also Dark Rye flour which is the whole grain milled with everything retained.
In the States things are a little more complicated as there is no single standard applied to flour extraction by the millers. King Arthur have a very good web page explaining this. https://www.kingarthurbaking.com/blog/2020/09/28/types-of-rye-flour
They recommend medium rye flour for general rye baking. This has had some of the bran removed, but it still retains a good rye flavour from the remaining bran. In the UK we can get something similar by passing Dark Rye Flour through a 1mm mesh drum sieve, or a kitchen sieve to remove some of the bran.
In the States there is no definition for Dark Rye flour. Sometimes it is what is left over after extracting the light rye flour. Other millers remove some of the bran and yet for others it is the whole rye grain milled.
King Arthurs Flour recommend using Pumpernickel four when whole rye flour is required as it is always 100% of the rye grain. Bob's Red Mill also have a pumpernickel flour. I am not quite in agreement with King Arthurs flour on this. Pumpernickel flour is very coarse indeed. It can be added to an over 50% rye flour bread at up to, say, 20%, to keep the texture open (see above), but it is too coarse to make a rye bread other than pumpernickel which is very dense indeed. Judicious use of it in a Borodinsky type of bread also works well. So too do small amounts (up to 20%) in an otherwise white flour wheat bread.
I have recently seen that there are now some millers which explicitly state that their rye flour retains all of the grains components. They sell their flour online too, in the U.S.
In some European countries there is an extraction scale and choices are generally clearer.
Malt
Diastatic malt contains amylase enzymes. It is counter productive in rye breads. Please do not use it!
Liquid malt is often used to confer a slight maltiness to the bread and to confer a little sweetness to the finished loaf. If using it the window is 4%-9% in a rye bread. Toom much will give a cloying flavour.
Ordinary malt contains sugars called maltose. These are the perfect food for LABS and yeasts. I wonder why no-one has ever suggests using very small quantities when getting wild yeast starters going?
Fermented Rye Malt
Fermented Rye Malt is central to some of the rich dark rye breads of the Baltic, Nordic, German, Ukrainian and Russian regions.
Fermented Rye malt is generally added at between 2%-10% of the total flour weight being used.
It can be found on eBay using a search for 'Fermented Rye Malt'.
Cocoa Powder
Some pro rye bakers recommend cocoa as a whole or partial substitute for Fermented Red Rye Malt. The cocoa does not impart a chocolate flavour, just deep rich flavours.
Substitute it for 10% of the Fermented Rye Malt, or use it instead of the Dark Rye Malt at 2%-10% of the weight of flour in the recipe.
Sourdough Pre-Ferments - Rye Sour Preferment.
As mentioned above rye loaf flavour balances well with some acidity. It also controls the enzyme activity which harms the finished loaf structure.
An instant yeast pre-ferment is poor for developing acidity and the acid produced is acetic acid which is not so good for flavour in a bread.
One Specialist Rye baking Russian Émigré said, "It is not possible to bake a rye bread without using a Sour Rye leaven." He is referring to Rye breads with above 50% rye flour.
The Sour Rye Leaven is used at between 20%-35% of the total flour used. This is using the percentage of rye flour in the leaven only, not the water weight. So for a bake using 500g of flour in total, 20% - 35% of that flour is in the leaven.
It is not possible to make a rye starter from rye flour and water and simply use it. It can take up to four weeks for the LABS to move into the natural leaven and establish themselves. For this reason I suggest that either a wheat starter, or a rye starter is established and used for wheat bread bling, or under 50% rye doughs, for a few weeks prior to baking an over 50% rye bread.
Make a Rye Starter
If you already use a sourdough, or natural leaven simply take 50g of it and give it a feed with rye flour and an equal amount of water. 100g of water and 100g will give you enough to make a loaf using 500g of flour at an inoculation rate of 20% by flour weight in the starter to the total flour.
Because rye has amylase enzymes along with superior mineral and other content, a rye starter is very easy to get going from scratch.
Take 50g of whole rye flour and add 50g of water. Mix it and cover it and leave it in a warm place. Within some 8 hours it should be just starting to bubble. When it does, add a further 50g of water and 50g of flour. Leave it a further eight hours or so. When it is full of bubbles one final feed of 50g of each water and flour are stirred in and it can be kept in the fridge for up to a week. If you want to keep it longer pop it in the freezer where it will happily keep for a year.
Tip: Adding a little rye flour to your wheat starter is an easy way to give it a boost.
Single Stage Sour Rye leaven
The rye starter we made above is a single stage rye leaven. Just make enough of it and leave it on the worktop overnight to build up some acidity.
For 1kg of flour in a bake: If we are using 20% rye preferment then 200g of that flour needs to be in the starter and the remaining 800g is going to be added when we make the dough up. As we are using a starter made up 50% water and 50% rye flour we need to add 200g of water to our 200g of flour. Mix this with 80g of the Rye Starter we made above (20% of the starter by flour weight) and stand it in a warm place and let it ferment overnight, or up to 16 hours and it's ready to use.
Two stage Sour Rye Leaven - This is the preferred method. For doughs using 1kg flour of less. (From Stanley Ginsberg)
Stage 1.
5g of the rye starter we made above.
50g wholegrain rye flour
50g water
Ferment it for 12-16 hours at 26°C-27°C
Then use this to make the second stage.
Stage 2 Leaven
Take all of the sourdough stage 1 leaven and add
100g whole-grain rye flour
65ml water
Instant yeast 1 pinch, or 0.0007 x the total flour weight in the recipe.
Total 270g
Hydration 70%
Ferment this in a warm place for 4-5 hours.
At a temperature of 27°C-28°C
This can now be used to make up the dough.
Remember to subtract the flour and water in the leaven from the flour and water in the recipe.
That is subtract
152g of Rye flour
117g of water.
The yeast is added to the preferment to boost the yeast population in it as the LAB population will dominate.
Scalds
These contain 10%–40% of a recipe’s total flour. Hot water at about 70°C – 80°C is mixed with the flour at anything from 100% - 200% the weight of the flour in the scald. A rye scald absorbs more water than un-scalded flour so increase the amount of water in the recipe by up to 20%. It is best to start with a 10% water increase and add more until the dough consistency feels right. This is because different rye flours and different extraction rates affect the amount of water required.
The water used in the scald is subtracted from the overall water when making the dough up.
Scalds add a soft mouthfeel, and moisture to rye breads. They also soften the crumb and improve the loafs keeping time. The scalding converts the starch into gelatinised starch. This process starts when the scald mix is 60°C or above. So it is important to check that the scald remains above 60°C for a few minutes. A short burst in the microwave oven, or using a bain marie will both achieve this end.
Fermenting the dough - Single fermentation breads
Some rye doughs are fermented once and others twice like most wheat breads.
If the recipe calls for a single fermentation shape the dough after mixing and place it in a tin, or banneton and let it rise until its volume increases by about 1½ to twice its original volume. When it starts showing cracks it is ready. Depending on the temperature this will take from 1 - 6 hours.
Otherwise ferment with a bulk fermentation and a proofing stage.
Bulk Fermentation
If a good acidic preferment is being used the bulk fermentation time is less critical. Bulk fermentation can be as low as one hour and be as long as six hours depending on the ambient temperature. With rye doughs that contain higher extraction rye flour (have less bran) we are looking for the dough to increase its volume by 1 ½ to twice its original volume. Doughs made with coarse rye don’t expand much. We are looking for a sweet, sour, fermented smell when they are ready.
Doughs using 50%-70% rye flour benefit from a couple of spaced coil folds to help the gluten development.
Dividing and Shaping
This will deflate the dough and that is alright. Shaping is pretty minimal as with doughs using more than 50% rye flour we are not working to develop gluten. For a tinned bread roll it up and pop it in the tin seam side down. For a free standing loaf shape it how you want and use a banneton.
Wet hands and a worktop misted with water are helpful for shaping as is the use of a scraper.
A worktop dusted with rice flour, durum semolina, or rye flour can be used for the final shaping, but try not to incorporate any into the dough.
Again if there is some wheat flour in the dough a couple of folds will help the gluten development. 100% rye flour doughs merely need forming into a shape.
Proofing
At the first sign of cracks forming on the top of the loaf it is ready. Rye bread comes to full proof quite suddenly. So, it is important to keep a close eye on them at this stage. Over proofing will lead to a gummy loaf. It's that amylase at work again. Proofing is generally one hour or less in a warm kitchen. (24°C - 28°C)
Pre-Bake
Docking the dough can be done to prevent the crust from bursting. Splitting , or bursting, is caused by steam bursting through the crust as it forms. Simply prick the dough all over the top using a chopstick or similar item. Using a lame to score the dough works as well, but there has to be a number of cuts covering the whole of the top of the loaf. A diamond, or squares pattern is attractive. Some rye breads crack all over and that is the way of them.
Another traditional technique is to make a scald (50g Rye flour and 2o0g water) and then baste the loaf before it goes into the oven and again immediately it comes out of the oven. This helps the loaf to retain moisture and improves it’s keeping qualities as well. It also gives the finished loaf a nice sheen. In the States it is common to use a corn starch slurry instead. Seed toppings can be added too.
If nothing else misting the loaf with water when it comes out of the oven will confer a slight sheen to the bread.
Baking
There are so many different ways to go with rye bread baking. The critical time is the first ten minutes. It’s important to have steam to allow the bread's oven spring before the crust forms and for the bread to pass 80°C quickly to stop the amylase enzymes breaking too much starch down. In Norway lidded wooden boxes were traditionally used. These work in exactly the same way as the Pullman tin which is my first choice as a way of retaining steam.
An oven temperature of 230°C- 250°C is a good range for the first ten minutes of the bake. The oven can then be reduced 180°C to 220°C for the remainder of the bake. For pumpernickels the oven is reduced to 100°C - 120°C and the bread is baked for up to 24 hours. This long slow bake caramelises the sugars and gives that very dark colouring typical of that bread.
When is the loaf baked
The best way to tell when a loaf is baked is by using a probe thermometer and measuring the internal temperature. Rye breads, being based on this gel complex, has a different temperature range from wheat flours.
60°C The hydrated starches start to gelatinize
63°C Gluten starts to harden. (Yes, there is some gluten)
71°C The gluten structure is fully coagulated.
90°C The gelatinisation of starches is complete and the loaf is fully baked.
Browning the Crust
Here a laser guided infrared kitchen thermometer is the tool of choice to measure the temperature of the crust.
When the crust temperature reaches 100°C, all of the surface moisture has evaporated and rapid warming begins.
At about 115°C, the Maillard reaction (Browning) Starts.
At 177°C, the Maillard reaction ceases and crust browning is complete. This is the same as with wheat flour breads.
Post Bake
As soon as the bread comes out of the oven it is time to use that rye flour scald/wash to baste the crust. Alternatively with North American Rye breads a corn starch slurry can be used. This glaze softens the crust and slows the escape of the steam. It keeps the breads especially moist for a couple of days.. It’s important to apply it as soon as the bread is out of the oven.
Another post bake treatment, again immediately after the loaf leaves the oven, is to moisten the crust with boiling water. This keeps the crumb moist while the loaf seasons. Rye breads stale very slowly. The high water absorbency of the pentosan-starch gel enables rye breads to stay fresh for up to ten days.
The flavour of rye breads continues to develop over the first few days after baking. Wrapping them tightly in grease proof paper keeps them moist during this process. A ziploc bag, or clingfilm will encourage moulding and they are best avoided. Rye breads are best at about three to four days after baking. During this time any residual gumminess decreases.
Cutting a rye bread made with 100% rye flour before 24 hours risks a very gummy crumb.
Rye breads freeze well.
These notes draw heavily on: Ginsberg, Stanley. 'The Rye Baker: Classic Breads from Europe and America'. He researched the topic thoroughly and his recipes are all based on authentic roots. His book is the best I have found for Rye Baking in the English language.
Other sources and technical papers have also been used.
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