I love winter squash but it is not always easy to eat it raw due to its dense and firm texture. This is where we bring in out little helpers, salt and lactic acid bacteria, to help break down the cell structures and render it pleasingly palatable via lactofermentation.
I came across two ways to lactoferment winter squash. In Ferment Your Vegetables by Amanda Feifer (2015), she ferments winter squash in brine, then blends it with tahini and olive oil to turn it into fermented winter squash hummus. In The Kimchi Cookbook by Lauryn Chun and Olga Massov (2012), they share a recipe for pumpkin kimchi, which is in fact a traditional Korean preparation during the winter squash harvest. This post will focus on the latter.
What is Hobak Kimchi
Pumpkin Kimchi is called Hobak Kimchi. The Korean word Hobak (호박) can be confusing because it is generic term applied to both summer squash (zucchini) or winter squash (pumpkin). To distinguish zucchini from pumpkins, some Koreans will call the zucchini aehobak (ae meaning white). Hobak kimchi is usually mixed with a small proportion of Napa cabbage to balance out the sweetness of pumpkin. The kimchi seasonings are the standard four stalwarts – gochugaru, garlic, ginger, and green onions. This kimchi is mildly spicy as you will want the pumpkin flavour to shine and not be overpowered by spice. Hobak kimchi does not usually contain glutinous rice porridge, perhaps because the high sugar content of the pumpkin is sufficient food for fermentation; and the texture of pumpkin is inherently slightly sticky, and even more so after fermentation. In place of tamari or fish sauce, I used a shiitake mushroom brine for umami as suggested in The Kimchi Cookbook, but used a 2% salt concentration instead of the 6% called for in the recipe because it seemed too salty.
How to Prepare Hobak Kimchi
The preparation of Hobak Kimchi differs from traditional cabbage kimchi. The pumpkin is soaked in a 3-5% brine, then rinsed, instead of being dry-salted. Separately, the cabbage is dry-salted at 1.5-2.5% salt concentration. You can adjust the salt concentration to your taste; I prefer a lower salt concentration. Typically, you use the brine method for root vegetables and vegetables with lower water content, and the dry-salt method for leafy vegetables or vegetables with high water content. The pumpkin and cabbage is then combined together and mixed with the kimchi seasoning, along with pumpkin seeds. The addition of pumpkin seeds add a nice texture and crunch to the ferment, as well as supporting the practice of “zero-waste,” if you go so far as to use the seeds scraped from the same pumpkin used for the kimchi.
Fermentation Time for Hobak Kimchi
Hobak kimchi ferments quickly because of the high sugar content of pumpkin. It should be ready in 2-3 days, depending on your climate. Do not over ferment or it will turn slimy. Check the ferment daily and once you are satisfied, store it in the refrigerator and let it age slowly. It is best eaten after 1 week of ageing (if you have the patience), and will keep for 3 weeks.
Taste of Hobak Kimchi
The final taste of Hobak Kimchi is really delicious. It is notably sweet with a hint of persimmon or apricot, tangy from lactic acid released during fermentation, umami from shiitake mushroom brine, and pungent from gochugaru, garlic, ginger, and green onion. The dense, hard flesh of pumpkin is brought down to a firm Fuyu persimmon, interspersed by pumpkin seeds. Hobak kimchi will become a treasured winter ferment, or even a staple kimchi all year long. It is that good.
Winter Hobak (Pumpkin) Kimchi
Pumpkin is given the kimchi treatment with gochugaru, garlic, ginger, and green onions in a shiitake mushroom brine. It takes on a soft, sweet persimmon-like texture and flavour. A delightful way to enjoy pumpkin raw!
To Prepare the Pumpkin and Cabbage
- 454 g (1 lb) winter squash, such as kabocha, muscat, or butternut (weight after peeling and slicing)
- 480 g (2 cups) 3% brine (15 g Himalayan salt + 480 ml warm water)
- 100 g (2/3 cup) Napa cabbage or red cabbage, plus one large leaf to use as a weight
- 2 g Himalayan salt or sea salt
- 8 g (4 tsp) gochugaru (Korean red chilli flakes)
- 3 g (1 clove or 2/3 tsp) garlic, grated
- 1.5 g (1/3 tsp) ginger, grated
- 6 g (1 stalk) green onion
- 12 g (4 tsp) pumpkin seeds or pine nuts
2% Shiitake Mushroom Brine
- 3.5 g (2 tbsp) dried shiitake
- 120 g (1/2 cup) hot water
- 2.5 g (1/2 tsp) Himalayan salt or sea salt
Prepare the Pumpkin and Cabbage
Peel and cut the pumpkin into 3 mm (1/8 inch) thick slices, then into 3 x 5 cm (1.2 x 2 inch) pieces.
In a large bowl, soak the pumpkin pieces in 3% brine for at least 45 minutes.
Drain the brine and allow the pumpkin to dry in the colander. To speed up the process, you can also pat dry the pumpkin with kitchen towels.
Meanwhile, in a separate bowl, toss the cabbage with 2% salt. Set aside for 20 minutes.
Rinse off excess salt from the cabbage, then set a colander above a bowl and allow the remaining water to drain into the bowl. Set aside the water that drains off the cabbage.
Prepare the Kimchi Seasoning and Hobak Kimchi
In a small bowl, combine the gochugaru, garlic, and ginger.
In a large bowl, combine the pumpkin, cabbage, kimchi seasoning, and mix very well until the seasoning is evenly distributed. Fold-in the green onion and pumpkin seeds. Do not over mix after adding the onion as it tends to get slimy.
Place the mixture into a sterilized glass jar. Pack the contents down tightly to remove any air pockets as you go.
Prepare 2% Shiitake Mushroom Brine
In a small bowl, soak the dried shiitake mushroom in hot water and for 30 minutes.
After 30 minutes, remove the mushroom and squeeze to release the juice. You can save and use the mushroom in other recipes. Add salt into the mushroom liquid and stir to dissolve.
To the drained cabbage liquid, add 80 ml (1/3 cup) of shiitake mushroom brine. Pour this mixture over the ferment until one-third to half of the contents are covered.
Cover and press down the ferment with the reserved cabbage leaf. Seal the jar tightly.
Ferment the Hobak Kimchi
Ferment at room temperature away from direct heat and light for 2-3 days. Taste the kimchi after 2 days to determine if the flavour and sourness are to your liking. If it is not sour enough, reseal the jar and let it ferment for another day or two, then taste again.
When you are satisfied with your kimchi, store the jar in the refrigerator and let it age slowly. It is best between 1-3 weeks of ageing.