Bulgarian Sauerkraut / Kiselo Zele

• 1.2 kg Green cabbage
• 0.150 kg Green apple
• 0.200 kg Onion
• 0.150 kg Quince (pear can be substituted if not available)
• as needed kosher/pickling salt (see note on pickling solution below)

1. 1 Remove the dark, coarse outer leaves from heads of cabbage and discard.
2. 2 Cut an "x" deep into the core of each cabbage, penetrating at least 2 inches.
3. 3 Place cabbages into a large container, preferably one that is large enough for the heads to be completely submerged under water but tight enough that the heads can stay wedged together and not float to the surface.
4. 4 Cover the cabbage completely with a known quantity of water.
5. 5 Cut the apple, onion and quince, if using, into quarters. Place in the water.
6. 6 Scoop a cup of the water into a measuring cup and dissolve enough salt in it to create a 3% salt solution (see notes for calculation).
7. 7 Pour salt solution into the vessel and stir everything together with a large wooden spoon.
8. 8 Place a plate or board on top of the cabbages to keep them submerged under water. Weight this down if necessary to keep it in place.
9. 9 Cover the vessel with a towel or other breathable cover to keep out debris but allow it to breathe. You can lightly cover it with a lid but do not tightly seal.
10. 10 Place the vessel in a cool place where it will not be disturbed. It's best to keep it around 70 degrees or so (a cool room temperature).
11. 11 Once a day, take off the cover and give the water a stir. If any white film or scum forms, skim it away. Add salted water if necessary to keep the cabbage submerged.
12. 12 After a few days, fish out the fruit and onions and discard.
13. 13 In about a month, your sauerkraut will be ready. Rinse it well and discard the brine.
14. 14 To create a 3% salt solution.
15. 15 Working in metric is the simplest way to make a solution. For a 3% salt solution, you will need 3 grams of salt for every 100 ml of water.
16. 16 Start by determining how much water you’re going to need in the vessel to cover the two heads of cabbage. Do this by measuring the water as you’re adding it. Multiply the total millilitres by .03 to get the grams of salt needed.
17. 17 Nutritional Highlights: this recipe primarily describes a whole-head lacto-fermentation process. The fruits and onions are used as a carbohydrate source for the brine's fermentation, but because they are discarded after a few days, the final nutritional profile is fundamentally that of sauerkraut. Here are the nutritional highlights of the ingredients and the final fermented product:
18. 18 Vitamin C: cabbage is highly concentrated with Vitamin C, which supports your immune system and acts as an antioxidant.
19. 19 Gut-Friendly Probiotics: through the lacto-fermentation process, the green cabbage transforms into a rich source of live probiotics. These beneficial bacteria promote a healthy gut microbiome and aid in digestion.
20. 20 Low Calorie Density: raw green cabbage provides only about 24 calories per 100 grams, making the final dish a highly filling, low-calorie addition to meals.
21. 21 High in Dietary Fibre: both cabbage and apples supply a great amount of dietary fibre, which supports healthy cholesterol levels and promotes satiety.
22. 22 Minerals & Potassium: cabbage and the assisting fruits provide potassium (which helps regulate blood pressure), as well as traces of calcium and iron.
23. 23 Antioxidants: cabbage contains antioxidants such as kaempferol, and the green apple skin contains flavonoids.
24. 24 (Note: While the fruits and onion are naturally high in sugars and carbohydrates, they are consumed by the beneficial bacteria during the fermentation process and then discarded in Step 12, leaving you with a low-sugar, tart end-product).

Sustainability impact

Wasted avoided: in the context of standard recipes, "waste avoided" typically refers to the weight or cost of food scraps (like peels, cores, or stems) that would normally be thrown away but are repurposed to prevent food waste. However, for this specific [Sauerkraut] method, the edible waste avoided strictly relates to the portions of your ingredients that are intentionally removed during preparation. The total discarded amounts include: Cabbage Outer Leaves (Step 1): the removal and discard of the dark, coarse outer leaves. Apple & Quince/Pear Cores (Step 5 & 12): the cores and seeds of the fruit, which are cut into quarters, submerged to flavour the brine, and subsequently discarded. Onion Waste (Step 5 & 12): the onion skins, ends, and quarters, which are added to the liquid and discarded with the fruit after a few days. In addition to preventing solid food waste, this fermentation method also serves as a long-term food preservation technique, essentially avoiding the waste of 1.2 kg of green cabbage and other ingredients by extending their shelf life for a month. By-product used: in this traditional Bulgarian sauerkraut (kiselo zele) fermentation process, the apple, quince, and onion act as a flavouring by-product. They leach their sugars and natural acids into the brine to kickstart the fermentation and add flavour, but are discarded after a few days so they do not rot Valorisation strategy: the valorisation strategy in this recipe is lactic acid fermentation via a controlled salt brine, paired with an upcycling/extraction technique. By using fruits and vegetables in the brine, the recipe utilises their natural sugars to fuel the fermentation, later discarding them as they have served their purpose as flavouring agents Circular economy principle: the core circular economy principle applied in this recipe is valorising by-products to extract their value and designing out waste. By using apples, onions, and quince strictly as extraction agents for their sugars and beneficial microbes, and then removing them, the recipe transforms raw ingredients into a resource-efficient fermentation medium without discarding them as conventional trash.