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Edible Crystals (Kohakutou)

by: Amy on: Jul 5, 2023

Edible crystals, or kohakutou, is a Japanese candy made from agar agar. Besides looking like real jewels, what makes these crystal candies so special is the texture — they have a crisp exterior shell while the interior of the candies are soft and jelly-like. The candies are a great blank canvas for any flavouring or colours of your choice. Because the base of these gummies is agar agar, these edible crystals are vegan!

Review  or  Print Recipe

I started making edible crystals last summer, when my friend Jacky developed an obsession with it after he got placed in some edible crystal algorithm on TikTok. When you’re stuck in a specific niche algorithm on a social media app, it makes something feel so much more commonplace than it really is. It seemed like everyone was able to easily access these crunchy (very ASMR-friendly) candies but in reality it was actually quite difficult to source locally. So I made some, recorded a video of the process, got Jacky to record some very satisfying crunching (or cronching) sound clips of himself biting into these candy gems, and shared the process in this Instagram Reel. Apparently being fascinated by edible crystals is not just a common interest between Jacky and myself, because so many of you wanted to make them too. Making edible crystals is a multi-day process but trust me, it’s a very hands-off process and the most important ingredient is just patience.

Edible crystals, also known as traditional Japanese confectionary ‘kohakutou,’ is a vegan candy made of agar agar. Agar agar is a thickener derived from seaweed — it’s a great alternative to gelatin and I like using it to set jellies and puddings… and now edible crystals! What makes edible crystals special and different from regular candy is that they have a thin shell with a firm jelly-like texture on the inside. If you grew up in a Chinese household, I would say the jelly texture of the candy is really similar one of my favourite candies I ate growing up, Smith’s Melon Candy.

Edible crystals only require four ingredients: sugar, agar agar, water, and your flavouring of choice. First, the agar agar is combined with water (much like blooming gelatin in water), and is brought up to a boil. Sugar and candy flavouring is then added to form a thick, translucent mixture. While the candy mixture is still hot, it gets poured into a heatproof dish. Before the candy mixture sets, food colouring (you can use as many colours as you like) is swirled in to create beautiful gradients that resemble real gemstones. Unlike gelatin, agar agar sets relatively quickly at room temperature so you can start carving the gemstones soon after you make the mixture. The candy mixture sets in about 15 – 20 minutes in the refrigerator and is ready to carving immediately after. Carving each individual crystal is by far my favourite part of the process. Using a small knife, remove small pieces from the edges of a crystal. There is no real technique to it — all gemstones are uniquely shaped and no matter how you carve it, it will turn out beautiful!

After all the crystals have been carved, it is simply a waiting game. On the first day, the candies are sticky to the touch and see through. Place the carved crystals on a parchment-lined baking sheet or plate, leaving a few centimetres between each candy. Loosely cover the crystals, it is important to not place plastic wrap directly onto the candies. I used a second baking sheeting to cover the pan of candies, leaving a small gap between the two baking sheets so the candies are able to dry. A thin crust will start forming on the second and third day, and this is when I like to flip each crystal over so the other side has a chance to form an even crust. The crystal will become less translucent and vibrant during the drying process. On day four and five, an even crust will have formed on all surfaces of the crystal. The crystals are ready to be enjoyed now but personally I found letting the crystals dry for one full week to created the best texture. Using edible gold paint and gold leaf to decorate the crystals is optional, but make the crystals even more jewel-like! Crystal candies can be stored in an airtight container for up to 3 weeks at this point.

Here is a separate batch with a different colour palette. I omitted edible gold paint and gold leaf on these ones, but they are just as beautiful. The photos show the crystals on the first day and on the fifth day after drying:

Edible Crystals (Kohakutou)

Edible crystals, or kohakutou, is a Japanese candy made from agar agar. Besides looking like real jewels, what makes these crystal candies so special is the texture — they have a crisp exterior shell while the interior of the candies are soft and jelly-like. The candies are a great blank canvas for any flavouring or colours of your choice. Because the base of these gummies is agar agar, these edible crystals are vegan!
Makes 50 pieces
By Amy

Ingredients

  • 350 ml (1 1/2 cups) cold water
  • 10 g agar agar powder
  • 550 g (2 3/4 cups) granulated sugar
  • 1/4 tsp candy flavouring
  • Several drops of food colouring

Instructions

  • Lightly grease a 8 x 8 square baking pan. Set aside.
  • Fill a medium-sized pot with cold water and add agar agar powder to the water. Allow the agar agar powder to absorb the water for 5 minutes.
  • While whisking, bring the mixture to a simmer and cook over medium-low heat until all the agar agar powder has dissolved, about 3 minutes.
  • Add granulated sugar and mix until all the sugar has dissolved. The mixture will be thick at this point. Add flavouring of choice.
  • Pour the sugar mixture into prepared baking pan.
  • Before the mixture sets, add a few drops of food colouring throughout the mixture, spacing out the food colouring. Using a butter knife or a spoon, run it through the mixture to gently swirl the colours into the sugar mixture.
  • Transfer the pan to the refrigerator. Allow candy mixture to chill until it has fully set, at least one hour.
  • Once mixture has set, run a sharp knife around the edges of the pan to loosen the candy. The candy should come out as one sheet.
  • Using the same knife, cut the sheet of candy into strips (I did 10) then cut each strip into 5 – 6 rectangular pieces. Shape each piece of candy by cutting off the straight edges at an angle.
  • Place the crystal candies onto a parchment-lined cookie sheet or large plate. Loosely cover the cookie sheet (without touching the top of each candy) and let dry at room temperature for 5 days (flipping the candies halfway through) until a hard crust forms on the outside. I like using a second cookie sheet to cover the first one while leaving a crack for air to get inside.
  • Optional: Using a small paint brush, brush edible gold paint along the edges of the candies and add edible gold leaf on the last day of the candy drying process.

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Recipe Rating




Sweet Comments:

  1. Morgan Bates says

    Dec 13, 2024 at 8:55 pm

    5 stars
    I’m SUPER stoked to try out this recipe. I have access to a dehydrator, could I theoretically use that instead of air drying? and for how long would I leave them in the dehydrator?

    Reply
  2. Sarah says

    Oct 14, 2025 at 6:02 pm

    I can’t wait to try these! What kind of flavors have you made? Do you add extracts as the candy flavor?

    Reply

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day two: sparkly matcha neapolitan shortbread cook day two: sparkly matcha neapolitan shortbread cookies ✨

the instructions might seem confusing, but if you watch the video to see how the different flavour layers are stacked, it will make much more sense! these slice and bake cookies freeze extremely well so you can make the dough now and bake them off when you want to gift them. (makes 40-44)

vanilla dough:
85g (1/3 cup + 2 tsp) unsalted butter, room temp
45g (6 tbsp) powdered sugar
2 tsp vanilla
90g (3/4 cup) all-purpose flour
1/4 tsp salt

matcha dough:
85g (1/3 cup + 2 tsp) unsalted butter, room temp
45g (6 tbsp) powdered sugar
90g (3/4 cup) all-purpose flour
2 tsp culinary matcha powder
1/4 tsp salt

strawberry dough 
85g (1/3 cup + 2 tsp) unsalted butter, room temp
45g 6 tbsp) powdered sugar
90g (3/4 cup) all-purpose flour
2 tbsp freeze-dried strawberry powder 
1/4 tsp salt

1 egg white
coarse sanding sugar

for the vanilla dough, combine butter and powdered sugar in a bowl. mix until smooth. add vanilla. add flour and salt and mix until no dry streaks remain. do the same for the matcha and strawberry doughs in separate bowls

place one portion of the dough between two pieces of parchment paper and roll into a 5 x 9-inch rectangle that is about 1/4-inch thick. slide rolled out dough onto a baking sheet and freeze for 10 min until firm. repeat this step with the other portions of dough

remove the top piece of parchment from each slab and stack the strawberry, vanilla, and matcha dough layers. cut the slab down the middle the long way to form two 2.5 x 9-inch rectangles. with one half, carefully swap the order of the layers (example: if the first half of the dough is stacked svm, swap the second half so it’s msv. this will ensure that same flavour squares don’t stack on each other). stack the halves. press the layers gently to adhere them. return the stacked dough to the freezer for another 10min

[recipe cont’d in comments]

#christmasbaking #christmascookies #holidaybaking #holidaycookies #cookiedecorating
day 1: rudolph rings 🦌✨ piped butter cookies day 1: rudolph rings 🦌✨

piped butter cookies are some of my fav cookies to make — they’re buttery! sandy! rich! they get a little holiday makeover and become the cutest rudolph rings when you add a little red m&m nose and antler details. topping the antlers with gold is optional, but adds extra sparkle and festive cheer to each cookie

(makes 12 cookies)
135 g salted butter, very soft
45 g icing sugar
100 g flour
40 g cornstarch
15 g cocoa powder 
1/4 tsp espresso powder 

in a medium bowl, combine softened salted butter with icing sugar with a rubber spatula until smooth

in a separate bowl, whisk together flour, cornstarch, cocoa powder, espresso powder, and salt

using a rubber spatula, fold in the dry ingredients into the butter-sugar mixture until no more dry spots remain

transfer the dough into a piping bag fitted with a large open star tip (i used wilton 6b)

apply pressure to pipe the dough onto the prepared baking sheet. if you are having trouble piping out the dough, you can warm up the dough in the piping bag between the palms of your hands, or add an extra 1 tbsp of melted butter to the dough and refill the piping bag. leave 1 inch between each cookie

transfer the sheet of piped cookies to the freezer while you preheat the oven to 325f. chilling the dough will prevent the cookies from spreading in the oven

bake the cookies until the bottoms are set, about 25 – 30 minutes

allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a cooling rack to cool completely and decorate

royal icing
1 egg white
150 g icing sugar
1/4 tsp vanilla extract 

in the bowl of a stand mixer or large mixing bowl, beat egg whites on medium-low speed until frothy, about 1 min. with the mixer on low speed, slowly add icing sugar and vanilla. once incorporated, increase speed to medium-high and beat until stiff peaks form. transfer icing to a pip bag with a small round tip to pipe out face details

#holidaybaking #christmascookies #christmascookie #holidaycookies #christmasbaking
sorry i cant come to the phone right now, i’m to sorry i cant come to the phone right now, i’m too busy baking all the @nytcooking holiday cookies the day they’re released

@csaffitz bûche de noël cookies
@samanthaseneviratne ginger cheesecake cookies
@heysueli matcha-black sesame shortbreads
@ericjoonho lemon-turmeric crinkle cookies
@clarkbar iced peppermint cookies
@sohlae holiday rocky road
@vaughn rum-buttered almond cookies

#nytcooking #nytcookieweek #nytcookies #holidaybaking #christmascookies
presenting: this year’s 12 days of christmas coo presenting: this year’s 12 days of christmas cookies 🎄

matcha christmas tree cookies 
chocolate reindeer cookies
matcha strawberry neapolitan checkerboard
hojicha walnut deer cookies (with a bow!)
hedgehog hazelnut praline shortbread
pretzel shortbread mittens
earl grey decorated wreath cookies 
snowman cookie butter truffles
grinchy pistachio jammy liners
eggnog brûlée cookies
biscoff snowman cookies
chestnut hazelnut praline sandwich cookies

…dropping tomorrow! stay tuned!

#christmasbaking #christmascookies #holidaybaking #holidaycookies #cookiedecorating
preparing for the big weekend… ✨ a tradition preparing for the big weekend… ✨

a tradition that i started in 2019, this will be the sixth year i bake all of the @nytcooking holiday cookies the moment they are released on dec 1. i’m excited/nervous for sunday (i might throw up). here are the cookies from previous years, and a few behind the scenes where you can witness me slowly lose my sanity.

2019: twelve cookies by @susanspungen
peppermint stripe cookies
color-field cookies
peanut shortbread with honeycomb
gingery brownie crinkle cookies
marbled tahini cookies
homemade pocky
abstract art cookies
stamped citrus shortbread
brown sugar-anise cookies
thumbprints with dulce de leche
blood orange poppyseed window cookies
dirty chai earthquake cookies

2020:
cornmeal lime shortbread fans
sparkly gingerbread
vanilla bean spritz cookies
toasted almond snowballs
honey-roasted peanut thumbprints
black and white brownies 
fudgy bourbon balls
cherry rugelach with cardamom sugar

2021: the year that @nytcooking released 24 holiday cookie recipes and i almost passed out/away
m&m cookies
almond spritz cookies
peppermint brownie cookies
brown-butter toffee sandwich cookies
hibiscus-spiraled ginger cookies
guava and cream cheese twists
minty lime bars
chewy gingerbread
savory mixed-nut shortbread
tahini thumbprints with dulce de leche
chocolate babka rugelach
fruity meltaways
iced oatmeal cookies
spiced orange crumble cookies
peanut butter cookies
gingerbread biscotti
cheddar cheese coins
fig and cherry cookie pies
italian rainbow cookies
chocolate-cherry ginger cookies
hindbaersnitter
no-bake chocolate clusters
torticas de morón
piparkakut

2022:
white chocolate macadamia nut cookies
gochujang caramel cookies
chocolate hazelnut cookies
gingerbread latte cookies
orange, pistachio and chocolate shortbread
crunchy coconut twists
savory shortbread with olives and rosemary

2023: last year’s seven cookies which was done after ten hours of baking
gingerbread blondies
mexican hot chocolate cookies
rainbow rave cookies
lemon butter curls
matcha latte cookies
technicolor cookies
neapolitan checkerboard

#nytcooking #nytcookies #nytcookieweek #christmascookies #holidaycookies

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