Having grown up in South Africa with the British influence of marmalade, I love the infusion and addition of citrus peel in dishes.  When our tangerine tree was begging to be picked, I decided to not only use the peel for citrus clove marmalade and citrus cranberry marmalade, but also add it to this walnut and citrus sourdough bread as an inclusion. Some friends came over and were interested in tasting this interesting looking bread and they LOVED it!  I made several versions of this bread to experiment with the peel and in the end, it's really personal preference.

 I also changed the technique of this sourdough bread to allow the sourdough to extract much of the micro-organisms in the wheat germ for maximum nutrition.  It may take extra time to proof, but it's well worth the increase in nutritional value. I also believe it affects the texture of the bread, making it softer.

Tips for making walnut and citrus sourdough bread

Walnuts.

I'm usually not a big fan of walnuts, but started to add them into my diet when I heard that walnuts are a superfood and especially good for brain function.  What is especially healthy is the thin papery outer layer which contains a high concentration of polyphenols.  This was the part of the walnut which I really hated and tried to remove!  In doing some research on polyphenols, I discovered that these polyphenols have an effect on plant coloring and may be a reason why this bread has the beautiful marbled effect.

Citrus peel.

For this walnut and citrus sourdough bread, I used tangerine peel.  I've experimented with tiny diced inclusions and grated peel.  The tiny diced peel give a more pronounced taste and the larger pieces definitely affect the texture of the bread.  If you like chunky marmalade, the tiny diced pieces will appeal to your tastebuds.  If you prefer a smoother texture and a more subtle citrus flavor, grate or zest the peel to avoid the pungent, white pith (tissue lining) of the skin. I also experimented using the juice but found that the effect on the flavor was not significant and actually, rather tart!

Adding Inclusions.

Since you want your walnuts and citrus to be uniformly distributed throughout the bread, it is best to add it during the stretch and fold process. This allows the inclusions enough time to be fully incorporated into the dough.  Adding it at the end will result in a swirl of inclusions which may look good but would really be a mouthful of nuts and peel!  Initially, the inclusions will not be completely incorporated in the dough.  However, after several stretch and folds, the walnuts and citrus peel will start to be uniformally distributed.

Proofing.

I have found that about a 36 hour cold proof is ideal for this bread.  After shaping and placing it in a banneton.  Allow the dough for this walnut and citrus sourdough bread to proof at room temperature for an hour (70 degrees fahrenheit or 21 degrees celcius) before placing it in the refrigerator.  The cold dough makes it easier to score and maximize fermentation.

If you make this walnut and citrus sourdough bread, let me know what you think in the comment section.