Fermented Garlic (Black Garlic)





Introduction: Fermented Garlic (Black Garlic)

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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

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

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

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

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

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.



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

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!

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.

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!!

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

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 http://translate.google.com.

These bakers cabinets cost a fortune.!

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.

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.

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