Introduction: Fermented Garlic (Black Garlic)

Picture of Fermented Garlic (Black Garlic)

I was introduced to "Black Gold" a few years back while I was cooking in Aspen Colorado.  It was brought into me by a vendor as a free sample and a new product.  Since that day, I have been determined to re-create the process for making black garlic. It took about 6 months of trial and error, but the final results were better than I hoped for.  The purpose of this Instructable is to give a very clear and clean cut process to making black garlic, this process was on my mind and there were tiny bits of information on the internet that dabbled in the process but none of them gave me clear directions.

Step 1: The Magic Fermenting Box

Picture of The Magic Fermenting Box

The most important piece of equipment that you will need is a fermenting box.  This little, or large, box will allow the garlic to sit at a consistent temperature for the allotted time.  I found that a wine cooler works the best because it is insulated, therefore it will hold the heat very well.  For the fan, I actually had an old hood unit from my stove that I replaced, so I kept the housing that the fan sat in and just cut the metal down to fit it into the wine cooler.  I also kept the switches in-tact to be used to control the fan speed and whether I want the light on or not.  
I now have a fan and two switches to control the two elements that will regulate and circulate my heat.  The last item that is need is a thermostat, these will run anywhere from $80-$120, all depending on what type you get.  The thermostat that I used came from Johnson Controls and they can be purchased here, this device will turn the power on and off to the box based on temperature.
Now go find yourself a vessel to make the garlic in, a device to heat the box with, a thermostat, and based on the size of the box, you will need a fan.

Step 2: Assembling the Fermenting Box

Picture of Assembling the Fermenting Box

The first step I took was to apply foil to the walls and the surface of the fan unit just below the light to contain the heat better.  Dark absorbs heat, light reflects heat, therefore we have achieved consistent heating.  To adhere the foil to the walls I picked up a bottle of spray glue, sprayed generously on the foil and on the inside of the box, let dry for a couple of minutes then slap that foil on there.  The next step was to mount the light fixture that I picked up from the local hardware store, I drilled two holes through the top of the box and through the lining on the inside.  I bought some full threaded, headless bolts, and using locking nuts to hold the light fixture in place.  As you can see there are two wires coming from the box, a hot (white) and a neutral (black).  I then cut down the fan housing to get it to fit into the box, this actually slid onto the existing rails for the wine shelves.  Again you will see two wires coming up from the housing and meeting up with the light fixture.  Drill one more hole in the top and feed those two sets of wires through the box and out the top.  I continued to run the wires down the backside of the box and let them hang for the time being.

Next, find a suitable place to mount all of your controls, if you do not have a fan or a switch, do not worry.  The switch for the fan that I have is adjustable, so I can change the speed of the fan, which also allows me to turn my fermenting box into an over sized dehydrator.  Anyways, the thermostat has built in switches to control when the lamp and fan should come on, and in this case the fan and light can be run on the same circuit because you want them both on at the same time.

Once the thermostat has been mounted, you are ready for wiring.

Step 3: Wiring the Thermo

Picture of Wiring the Thermo

The instructions that come with the thermostat are not user friendly unless you know how the switches and electricity works.  I will make it as easy as possible to understand.

When you remove the cover to the thermo you will see a coiled copper wire, this is what reads the temperature, gently stretch it out to the length that you will need.  I fed this wire through the side of the box and secured it to the bottom of the box.  There will also be three screws; The top one is yellow, the middle is blue, and the bottom one is red, you will not be using the yellow screw.  Find a cord that you will be using to plug into the outlet, this can come off of an old fridge or in my case, the wine cooler.  Clip the cord, and separate the wires, strip the wires (Two if you have two prongs on your plug or three if it has a ground/three prongs), gather all of your white wires and splice them together securely.  All of your white wires, including the one from the outlet cord should be spliced and secured together.  Now take the black wire from the outlet cord and secure it onto the red screw.  Take the remaining black wires and splice them together with an extra black wire, run the remaining black wire to the blue screw and secure.

Screw a light bulb into the socket, plug in the box, and you are ready to begin the black garlic process.

Step 4: Starting the Garlic

Picture of Starting the Garlic

The hard part is over and now it is time to begin fermenting garlic, this process requires patience, because it will take 40 days.  After a few trial runs, which can be found on my blog, I found that the best vessel to put the garlic in was an aluminum baking pan.

Start with 2.5# of fresh cloves of garlic, place them in an even layer in the baking pan, cover with plastic wrap (make sure to wrap the baking pan all the way around to ensure a nice tight seal), then a layer of aluminum foil.  The purpose of the plastic is to keep the humidity in, the foil helps keep the heat even.  Set your thermostat to 140 degrees, close the door, and hurry up and wait.  I found that after the garlic has started it requires very little attention, the room that the box is in will smell of fresh garlic and will gradually change to a nice roasted garlic smell.  My first batch of garlic was started in my living room, after 40 days my clothes smelled of roasted garlic, not necessarily bad but I eventually moved the box to my garage.

After 40 days open your pan of garlic and take in the glory, you should be able to gently peel back the paper like skin protecting the clove and visibly see a color change.  If it looks black then you are headed in the right direction, next grab a clove and squeeze it between your fingers, it should turn into a paste.  If it does not and it still feels firm then you have not achieved a finished product.  This usually happens when the heat is uneven, wrap the pan again with plastic and foil and continue to ferment for an additional ten days.  I found that having the pan sitting on some wire racks so it was elevated to allow the air and heat to circulate, I was able to make the product in 30-35 days.

The next step is the drying process which can take three days to a week.

Step 5: Drying Your Black Garlic

Picture of Drying Your Black Garlic

Once he garlic has the proper color and consistency you can begin to dry the garlic which will do two important things.  The first; it will intensify the flavor and color of the garlic.  The second, it will remove excess water that will allow the garlic to last longer under refrigeration or out in the open.  I do not know its perish-ability yet on the open shelf so I keep mine under refrigeration.  Remove the garlic from your baking pan and place on the wire racks.  Keeping your heat at 140 degrees, close the door to the box and allow the garlic to dry out for four to five days.  At this point the finished product is all up to you, I removed all but a few samples which I left in the box for two more weeks to remove all of the moisture and now have a dried black garlic that can be turned into a powder.  There are many uses for black garlic and now you don't need to pay the ridiculous prices online or at the store.  Black garlic is now considered a superfood and more info on its health benefits can be found online.

For my full process and experiments you can visit my blog.


MoiraS1 (author)2017-06-26

I bought a formenter done in 11 days easy as pie easier than pie

Jagstah (author)2012-05-08

Hi, I have been following your DIY blog since April and I thank you for publishing your process. My wife pointed out that there might be a health risk when using plastic wrap as the shell for the fermentation process. Do you think that moisture dripping down from the plastic wrap in a box heated to 140 degrees will pose a cancer risk? Perhaps it would be better/safer to use glass containers instead? Best Regards!

akulinary (author)Jagstah2012-05-08

Thank you for the comment, I have looked into the plastic issue and commercial plastic wrap has a different makeup than the plastic wrap you would get at the grocery store. I am currently looking into an alternative and actually adding a humidifier or a mister to the box so I do not need to wrap it. I will be starting that project after I finish my meat curing cabinet.

Jagstah (author)akulinary2012-05-09

All of my research from the past 7 months has led me to the now obvious conclusion that what is needed to make aged black garlic is a typical baker's fermentation cabinet. In German we call this a "Gärschrank" and this machine allows operators to individually adjust temperature and humidity. For the life of me I cannot understand why anyone would want to patent a new machine and process for making black garlic when millions of existing bread machines can already do it. Hats off to you though, for making your own and publishing your results!!

CindyH143 (author)Jagstah2017-02-11

Can you tell me a little info on the bakers cabinet?

Jagstah (author)CindyH1432017-02-12

There is a german wikipedia page about it here. If you cannot read German and your browser doesn't offer to translate the page for you, try entering that wikipedia URL at

tirnanog33 (author)Jagstah2015-03-25

These bakers cabinets cost a fortune.!

akulinary (author)Jagstah2012-05-09

Never new that these machines existed! Thanks for the info, I will look into getting one or figuring out how to make my own. I am certainly not trying to re-invent the wheel here, I am just cheap, my box uses very little electricity and is very efficient at what it does, and in all of my research on black garlic no machine ever came up. I think the guy who is monopolizing on black garlic did patent his machine or the process, not sure though.

Jagstah (author)akulinary2012-05-09

For sure, those "Gärschränke" (<-- link to google pics) cost a lot of money new so it is probably worthwhile to DIY if not trying to sell the stuff commercially.

A group of Koreans named Duck, Han and Sung filed a patent for a machine in 2010 which you can see online here. Also check out the pdf file linked on that same page, which includes a sketch of a fermentation machine which I believe to be the machine shown here.

FWIW I did not know much about the fermentation process before getting interested in black garlic and I'm no pro baker but now I believe that someone is trying to trick us into thinking that there is some magical, secret process to making this stuff when in reality it is as simple as baking cupcakes for 3 weeks.

timbit1985 (author)akulinary2012-07-06

Just cut a piece of glass to size over your fermentation tray. OR put a bowl of water on your element.

akulinary (author)timbit19852012-07-19

Great idea! I have started another project and will give it a try as soon as I am done.

MsJan (author)Jagstah2012-08-03

Glass is always the safest way to go. Always stay away from plastics. They do cause cancer. I wish these companies would start making things that are safer for humans.

akulinary (author)Jagstah2012-05-08

On the glass baking dish, I started my experiments with glass mason jars and I did not get a final product that I was happy with.  Another technique that I will try is with parchment paper.  I use that a lot when braising foods followed by foil and that will help keep moisture in.

Jagstah (author)akulinary2012-05-09

What do you think about using some kind of pyrex dish with a lid made of the same material?

akulinary (author)Jagstah2012-05-09

I used mason jars previously, and i did not get the results that I was looking for.

Jagstah (author)akulinary2012-05-09

What kind of results did you get with the mason jars exactly?

sont27 (author)2016-08-16

Black garlic fermentation machine, The reason to use this machine to make black garlic

Shorten the fermentation time is only 12 days. You will not have to wait nearly two months to be using black garlic as handmade anymore.

Energy saving 5 times compared to using fermented rice cooker black garlic. Every month you have saved a considerable sum of money for his family.

Implement automated fermentation with only one button. Extremely easy to use, even elderly people can use right from the first time guidance. Easy to use than the rice cooker.

Fermentation success ratio reached almost 100%. Did was certainly successful.

Ensure black garlic produced the best quality. If you follow instructions, ensuring good quality like black garlic purchase price of 1 million / 1 kg in supermarkets.

Material is ABS plastic manufacturing and ultra heat-resistant alloy, durable. The unit can operate in an extended period of time without fear of damage.

Modern design, easy to place anywhere in your kitchen without fear of affecting beauty.

You can not buy health products, but you can not ignore this machine is Black garlic fermentation machine. We are sure that it will benefit many times more than the cost you money. This machine is black garlic is a breakthrough product in the field of health care research and experimental years of leading scientists in the world.

CindyH143 (author)sont272017-02-11

Thank you for all your info, i am interested in this site, do they have an english one?

rogermv (author)2017-01-18

I adapted a machine to make black garlic I have been successful except for some attempts in which the garlic gets very hard like a rock. The garlic stays at a temperature of 70ºC and humidity around 80%. Can someone help me?

futurebird (author)2016-10-30

$100 is to much to pay for a thermostat. Here is an $8 one.,searchweb201602_2,searchweb201603_1&btsid=63d4ac3a-6cf3-42c5-91e4-ca1abe3883ac

Anon q (author)2016-04-04

I'm confused... Are you using microbes to turn the sugars in garlic into alcohol, gases, or acid? OR are you using heat to slowly modify the sugars? Because one is fermentation and the other is a Maillard Reaction and they're completely different.

U V (author)Anon q2016-09-17

They call it fermentation but it is really the Maillard reaction. The trick is heat and time but not hot enough to breakdown the antioxidants and it does seem to improve the quality of all the good chemicals.

Afaflix (author)Anon q2016-04-21

at 140 degrees for days, this is a breakdown process, not a fermentation

Although the process is consistently described as “fermentation,” it really isn’t that in the strictest sense, as the transformation does not involve microbial processes—specifically, enzymatic breakdown and the Maillard Reaction are responsible for the caramelization of the sugars, dark color and deep, complex flavor profile.

Ngọc LanA made it! (author)2016-08-16

I make black garlic with this machine, and to easy, i don't care about degrees or time

rush_elixir (author)2016-02-16

you can make black garlic in a rice cooker with keep warm takes 9 days not 30 days because it will become crispy black in the rice cooker method...warning though...about the smell...need to place your rice cooker with garlic in a well ventilated place not indoors due to smell of it while its fermenting/caramelizing process...just search youtube for videos on how to make it the rice cooker way.

CharlesC95 (author)2016-02-13

Many very sensitive food and food ingredient products are packed and processed in Mylar bags. At these temperatures, these bags should be inert (not give off any odors or risky chemicals). This is much better than "Saran Wrap" products which are PVC and always give off nasty vapors when heated.

NoPinky (author)2016-01-02

Thanks for sharing the information, maybe you can explicitly tell that it is 140°F. Because most of the Non-Americans use °C.

MickyL1 (author)2015-11-09

I'm sorry about picking your nits, but your pictures show heads of garlic, not individual cloves. I think you should edit this post, changing "clove" to "head". Without the pictures, one might break all of those heads into individual cloves before fermenting them. I suspect that's not what you had in mind.

manikrk (author)2015-09-17

Thanks a lot. I will keep it in mind. I will share the result when it is ready.

manikrk (author)2015-09-04

Hello, I am from Nepal. In Nepal we have electricity supply only 12 hours in a day with breaks in between. Heating the box with 100W bulb in such circumstances, will it be okay if I keep for 80 days instead of 40 days ? Thanks in advance.

akulinary (author)manikrk2015-09-16

Hey there! Sorry for the delay, if the insulation on the fermenting box is good then you shouldn't need to worry about it. I would set the box a degree or two higher than normal and it should hold the average temp that you want.
Adam Kapela

tirnanog33 (author)2015-03-25

Hi, can you tell me what kind of heating elements you used and what wattage.?

also the purpose of the large lamp.? thanks.

akulinary (author)tirnanog332015-03-27

The purpose of the lamp is to heat. Therefore there is no other heating element. I think the wattage is 100w heating lamp.

CoreyW1 (author)2015-03-21

An electrical safety correction:

White Wire = Neutral

Black Wire = Hot (phase)

pb404 (author)2015-01-17

This proofing/fermentation box is pretty affordable

jscene (author)2015-01-03

I just loaded up my rice cooker with garlic. I found a recipe that calls for nine days in a rice cooker on the "keep warm" setting followed by a week on a drying rack. I can't wait to see how this works as my wife planted about 7#'s of garlic in the fall. I hope to be up to my eyeballs in black gold soon! I'm concerned that the hole in the top of the rice cooker may allow too much moisture out and that nine days isn't long enough, but there's only one way to find out!

akulinary (author)jscene2015-01-05

Can't wait to hear about it! You could try plugging the whole with something to help prevent moisture loss. Maybe a little electrical tape to cover the whole? Good Luck and let me know how it works out!


jscene (author)akulinary2015-01-05

Will do Adam. I decided to leave the hole open and see what happens since this is my first time. I've read cautionary tales about too much moisture and not enough moisture... so we'll see! I also decided to put a head of elephant garlic in just for grins. Stay tuned!

troy.borrero (author)2014-12-04

I just finished my fermenter...well multi use project box....I got digital tempature controller from eBay for $15, wall outlet, appliance plug, small box from hardware store..wired the controller to one of the outlets so now I can plug a crock pot into it then cut the box so everything fit. Later I can use the same box for incubator, dehydrator, fermenter. I wired the other outlet for constant power so I can use it for a fan. the wiring was the hardest part for me. But it's holding 140F nicely!

so after fermenting for 15 days I gave garlic flavored rocks....bust...a lot of moisture inside the croc pot but still dehydrated very hard garlic..I added a glass of water today to get them to rehydrate maybe...they are black though

akulinary (author)troy.borrero2014-12-22

yea it sounds like it just got too dry, thats what i experienced my first few attempts. You want the garlic to keep most of its moisture for the first 30 days or so. After you get the nice color from aging aging around 35-40 days then you dry it out for 2-3 days to get the intense color and nice paste like texture. Mason jars did not work well for me but a baking dish with plastic and foil did. Someone else mentioned parchment paper, may work but still very porous.

troy.borrero (author)akulinary2014-12-22

When I started I put a damp towel on top of them (it was still damp) the lid had tons of water drops on it and wrapped the lid in plastic wrap to keep it sealed...even the sides of the cloves were damp...but inside was a slightly shriveled black cloves that were hard as rocks.

rainbowsly78 (author)2014-11-17

What about using a convection oven even the small toaster convection oven. it Has the fan the heat and the temp gauge?

akulinary (author)rainbowsly782014-12-22

its possible as long as the garlic is protected from the moving air.

PatO1 (author)2014-10-28

In Japan, people are using rice cookers to make this. I'm not sure what the temperature is. They are saying about 60 degrees C, but the garlic is black and very nice smelling in about ten days. You load the rice cooker with garlic, set it on "keep warm" and open it up once a day to rearrange the garlic. It comes out fairly moist, so it may need subsequent drying in order to preserve it. We are experimenting with this.

power.suppermen (author)2014-09-28

hi you,i'm student of university in
vietnamese, i really like product garlic, i dont understand about their
mechanism, why did white garlic became black garlic?, i want understand
it, i hope you can help me, please. thank you very much!

i learn english very bad. ^.^

Nedalice (author)2014-08-21

Do you think if I put it under the aquarium hood would work?

black garlic (author)2013-06-25

Hi, Are you using a humidifier or a mister to the box, and how does it works? waiting for further information..

akulinary (author)black garlic2013-06-26

No humidifier in this box, I let the garlic create its own humidity when wrapped up in the baking pan. The humidity should stay pretty high until you need to dry the garlic so a bowl of water would work fine if you do not have a humidifier.

black garlic (author)akulinary2013-12-07

thanks for your reply, I have already made it.

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