9  Mix-ins

In this chapter, you will learn about the fascinating world of sourdough mix-ins. Discover how these additions can elevate your bread, enhancing flavor, adding vibrant colors, and creating delightful textures that make each loaf a culinary masterpiece.


Figure 9.1: These soft pull-apart sourdough buns have been made with the addition of pumpkin purée. The mashed pumpkin adds flavor and hydration to the dough.

A loaf of wheat sourdough has a very pure aesthetic. Good craftsmanship and precision transform the ingredients into simple, but delicious food. With mix-ins, the basic recipe can become the starting point for a whole world of modifications to try and combine. Think of the loaf of bread as a blank canvas to express yourself.

9.1  Categories


Figure 9.2: A common mix-in technique is to replace some of the dough’s water with another liquid. In this case, puréd pumpkin replaced some of the water. When adding puré to the dough only slowly add additional water as the puré slowly releases additional water to the dough.

One approach to categorizing the mixins is to look at their respective shape. However, the transition between these categories is somewhat fuzzy:

  • Liquids: Integrate homogeneously into the dough, may replace some of or all of the water. Examples: Milk, butter, oil, spinach juice, tomato juice, eggs
  • Powders: Integrate homogeneously into the dough, may replace some of the flour. Examples: Milk powder, semolina, cocoa, spices
  • Small bits: Individually visible in the final loaf, small enough to distribute somewhat evenly throughout the dough. Examples: Seeds (wheat berries, rye berries, poppy seeds, sesame, pumpkin seeds, flax seeds), whole spices (coriander)
  • Chunks: Larger pieces that will only be present in the occasional bite when eating a slice of your bread. Examples: dried tomatoes, chunks of cheese, chunks of chocolate

Another categorization approach looks at the changes to the bread:

  • Flavor: Significantly changes the taste of the bread. Examples: rye flour, corn flour, spices, sugar.
  • Color: Significantly changes the look of the bread. Examples: cocoa, squid ink, beetroot juice, tomato juice.
  • Texture: Significantly changes the feeling in the mouth when eaten. Examples: Cheese (gummy), seeds (crunchy), olives (squishy chunks).

Many of the above-listed mix-ins can’t be pinpointed to a single category. They change multiple aspects of the final bread at the same time.


Figure 9.3: In this case a combination of flax, sunflower and sesame was added to the dough. The seeds will slightly dehydrate the dough during fermentation and thus adding a bit more water (1 % to 2 %) is advised.

Mix-ins affect the structure of the dough. One aspect is the impact on hydration. Some mix-ins absorb a lot of water when added to the dough, so you have to increase the amount of water to achieve the same dough consistency. The other impact is on the gluten network. Bits and chunks disrupt the gluten network and may reduce oven spring during baking. All of this depends on the amount of mix-ins used. A good rule of thumb is to add 10 % to 20 % of the amount of flour in most mix-ins, reduced to around 1 % to 5 % of the amount of flour for spices.

An important factor is also the mix-in’s behavior during baking. Particularly chunks may bake differently than dough, and either melt (cheese) leaving holes inside, or char when peeking through the crust (e.g. vegetables). These problems can be mitigated to some degree with the right preparation (e.g. chopping into smaller pieces, soaking dry ingredients in water or oil first, or squeezing out excess moisture).

9.2  Examples

The following is a list of common mix-ins and their peculiarities. They can be combined depending on your preference.

9.2.1  Flours

These are powders. Usually, you want to just replace some fraction of the regular bread flour. Different flours change the taste of the bread and usually moderately affect the color.


Figure 9.4: Broa de milho is a traditional Portuguese bread made out of half rye and half corn flour.
  • Whole wheat flour (substitute any amount, makes the bread taste more complex, nutty)
  • Rye flour (very hearty, nutty, malty taste)
  • Enzymatic malt (malty taste, improves enzymatic activity). The malt is a great addition when making quicker yeast-based doughs.
  • Semolina (supports Mediterranean flavors)
  • Cocoa (replace 10 % of the flour for a black loaf, goes great with sweet toppings)
  • Other non-wheat flours such as: Chickpea, corn, hemp, potato etc.

9.2.2  Liquids

Instead of using water, you can substitute it with a different liquid, affecting taste and texture.


Figure 9.5: Dark hearty stouts work excellently as a water replacement when making sourdough bread. The resulting loaf features a hearty malty taste
  • Beer
  • Butter
  • Buttermilk
  • Cereal milk (the leftover milk from eating cereals)
  • Coffee
  • Eggs
  • Fruit/vegetable juices (also see Section 9.2.3)
  • Milk (for sweet, soft breads)
  • Milk alternatives such as: Almond, oat, soy etc.
  • Mashed potatoes
  • Mashed sweet potatoes. Bolo do caco is a typical bread from Madeira, made from 50 % wheat flour and 50 % mashed potatoes.
  • Olive oil (Mediterranean)
  • Other mashed vegetables such as: Beets, pumpkin, etc.

9.2.3  Colors

Some mix-ins will change the color and flavor of your bread. Common colorings include:

  • Activated charcoal powder (black)
  • Beetroot juice (red)
  • Blueberry juice (blue)
  • Blue butterfly pea flower powder (blue)
  • Carrot juice (orange)
  • Pear juice (pink)
  • Spinach juice (green)
  • Squid ink (black)
  • Strawberry juice (red)
  • Tomato juice (red)

9.2.4  Seeds and nuts

These are small bits, with some almost crossing into the chunk category. Some seeds benefit from being boiled for about 10 minutes before adding them to the dough.


Figure 9.6: The Stollen is a traditional German sweet Christmas bread featuring a variety of mix-ins. The dough typically contains candied lemon, candied orange, and raisins. The mix-ins are soaked in rum before being added to the dough. While the stollen matures after baking (up to 6 months) the candied ingredients release their aroma to the baked product.
  • Cacao nibs
  • Chia seed
  • Chopped or whole nuts such as: Almonds, hazelnuts and walnuts
  • Flaxseeds
  • Hemp seed
  • Poppy seed
  • Pumpkin seed
  • Sesame
  • Sunflower seed
  • Whole rye berries (boil 10 minutes)
  • Whole wheat berries (boil 10 minutes)


Figure 9.7: A sourdough bread made with half whole-rye flour and half rye berries. The berries are typically boiled for 10 minutes to allow them to soften a bit. When baking a loaf it is advised to use a thermometer to measure whether it is done baking. The final bread features a hearty tangy flavor and has a moist crumb.

9.2.5  Spices and flavor mix-ins

These are mostly powders or small bits.

  • Blueberry skins (press through a sieve to remove juice, raw blueberries
  • Browned onions
  • Candied fruits such as: Lemon, orange, pineapple, etc.
  • Cinnamon
  • Grated hard cheese such as: Gruyère, parmesan, etc.
  • Mediterranean herbs such as: Marjoram, oregano, rosemary, thyme, etc.
  • Miso
  • Molasses
  • Sugar
  • Spices such as: Anise, fennel, cinnamon, coriander, cumin, etc.
  • Zests such as: Lime, Lemon, orange, etc.

9.2.6  Highlights

Mostly chunks, that add a big contrast and flavorful highlight to the basic bread. Usually, you want to use only one (or a maximum of two) of these. The suggestions can often be complemented by some flavor or flour mix-in.

  • Chocolate chunks or drops
  • Chunks of black garlic
  • Chunks of cheese such as: Cheddar, feta, etc.
  • Cornflakes
  • Dried fruits such as: Cranberries, dates, raisins, etc.
  • Olives
  • Pickled pepperoni
  • Sundried tomatoes (squeeze out the oil if using pickled ones, or soak dried ones in water)

9.2.7  Combinations

A few combinations where multiple mix-ins complement each other:

  • Butter and milk. Then add cinnamon and brown sugar before shaping
  • Cheddar and pepperoni
  • Cheddar and jalapeño
  • Cocoa, cacao nibs, whole hazelnuts
  • Cranberry and walnuts
  • Semolina, Mediterranean herbs, olives, sundried tomatoes
  • Tomato juice instead of water with 20 % rye flour

9.3  Techniques

Adding mix-ins to the dough is just the simplest approach. Add the mix-ins directly when you knead the dough. After the first kneading wait for 30 minutes to see if the dough has enough or too much water. In the case of whole-soaked berries (e.g. rye or wheat) chances are that the berries will release some water and make the dough wetter. In this case, you will want to add a bit more flour to the dough to compensate for the high hydration.

9.3.1  Adding before shaping


Figure 9.8: A great technique is to add some of your mix-ins directly before shaping. In this case, a mixture of apples, cinnamon and brown sugar was applied. Proceed and roll the dough together. Afterward cut the roll into smaller pieces using a sharp knife, dough scraper or dental floss. Place each piece of dough next to each other in a greased bowl to allow them to be proofed. Proceed and bake as you would normally do. The benefit of this technique is that the mix-ins will not be fermented. This is typically required in the case of sugar since you want the final baked goods to feature sweetness. If included upon initial mixing most of the sugar would be fermented and the bread would not taste sweet.

Another approach is to lay the dough out flat after the bulk fermentation. Then using a spatula spread your ingredient over the flat dough. Continue with your regular shaping and/or roll up the dough. When creating a roll you can use a sharp knife to cut the dough, dental floss works great too. Afterward, place the tiny swirls in a container to let them proof and become fluffier. This is an excellent way to add sweet mixins as the microbes will not ferment them. When adding sugar to the initial dough it will be fermented and the resulting dough will not taste sweet (depending on the fermentation duration). This approach is excellent for garlic/cheese rolls, garlic/herb rolls, and cinnamon rolls

9.3.2  Covering the surface


Figure 9.9: These are chop buns which are created by chopping up a retarded dough into smaller pieces before baking. Then each piece of dough is quickly dumped in water and then rolled in a bowl of seeds. Afterward, the dough is directly baked in the preheated oven. These coverings add superb additional flavor and can be adjusted depending on your preference. I love adding a mixture of sunflower, flax, and sesame seeds.

This works best for either powders or small bits. After shaping wrap your coverings on the dough’s surface. This works great too when covering your banneton or loaf pan with seeds or oats. When using a loaf pan or banneton these coverings also help to make the container stick less.

Another approach commonly used with buns is to wet the surface or dump the dough in water. Afterward, dip the wetted piece of dough into your bowl of mixins. This does not work for all mix-ins, as some can’t handle the high temperatures during baking and char. Most commonly done with seeds (e.g. sesame, oats, flax-seed).

9.3.3  Swirled colors

Mix-ins that change the color of the dough bring the opportunity for even more creativity by merging the dough before shaping.

Proceed and separate your base dough before adding a colorful ingredient. Bulk ferment the dough in separate containers. Then Combine the two (or more) differently colored doughs by laminating and stacking the colored sheets of dough before the last folding, just before shaping. This way the colored layers won’t mix and the resulting dough will have differently colored and tasting layers.1

1I once made an experimental dough by merging a wheat, rye, spelt and einkorn dough into a single dough. The resulting dough was layered featuring different colors, textures, and flavors.