Clearing Mead with Bentonite (clay)

1) What is Bentonite?

Bentonite is pure powdered clay and is used in wine and mead making. It is inert and tasteless. You can get it at your local homebrew shop or by mail order quite inexpensively.

Bentonite is used during racking to flocculate out the leftover yeast so that it settles to the bottom, leaving crystal clear mead behind. The clay particles are tiny flat sheets of mineral with minute electric charges sticking out at the edges. These charges attract the yeast cells, which then stick together in visible clumps that settle out rapidly.

The time to bentonite is any time after active bubbling ceases. If you bentonite while there is still fermentation activity, the yeast that settles to the bottom will keep bubbling and re-cloud the mead. If you use a yeast nutrient, fermentation will proceed rapidly and cease in a month or so. By using bentonite, your mead will be clear and ready to bottle in a few days, freeing your carboy for more mead!

2) Bentonite Preparation

Use 1/2 tsp bentonite per gallon of mead to be clarified. To prepare the bentonite for 5 gallons, boil 1 cup of water in a small saucepan. Pre-measure 2 1/2 tsp of bentonite granules into a small bowl. As the water boils, SLOWLY sprinkle in the bentonite, stirring occasionally with a fork.

If you sprinkle it in too fast, the granules will stick together as they absorb water, making large thick clots, which is not what you want. If that happens, just throw it out and try again.

If you sprinkle just right into the boiling water, it will stay soupy. Take it off of the heat and store covered for 24 hours while the clay goes completely into suspension.

3) Racking Procedure

Fill a clean pot with water, and bring it to a rolling boil for 10 minutes to drive off all of the oxygen. This water will be used after racking to fill up the head space. If you leave a head space after racking, the oxygen in the head space air will get into the mead and produce flat off flavors.

Stir the bentonite mixture with a fork to get it all into suspension. Pour the bentonite mixture into the second (empty) carboy. Then rack from the first carboy into the second. Avoid splashing, which will oxygenate the mead. Top off the head space with the boiled water. Stir the mixture thoroughly without splashing by rotating your J-tube in the carboy.

The bentonite will bind with the yeast into visible particles and flocculate out fairly quickly. After two days or so, it will all be resting in the bottom 1/2 inch of the carboy.

Sometimes there is so much yeast in a mead that the first bentonite cannot flocculate out all of the yeast. In that case, do it again. The result will be crystal clear.

Clarifying mead with gelatin is similar to using bentonite. Powdered unflavored gelatin is available in most grocery stores (the Knox brand is probably the most widely known). I generally dissolve a packet of the powder into 1 cup of cold water in a pot. Heat this on the stove, swirling gently, until it's all dissolved. Cover it and let it sit 20 minutes to pasteurize it. Warning: do *NOT* let this stuff boil over! It's very difficult to clean up!

Put the pot somewhere where you can grab it easily, and start siphoning your mead into an empty carboy. When there's a gallon or so in the new carboy, take the gelatin solution, and slowly drizzle it in (if you dump it directly into the empty carboy, it will just coagulate on the bottom in a useless lump). Finish siphoning, and stir if necessary to distribute the gelatin evenly throughout the carboy.


Expirament with this one. You want to melt the gelatin, but you don't want to let the water boil. I've found 45 seconds in the microwave, stir, let sit about 2 minutes, and stir some more works well for me. Your mileage may vary.

The two most useful things in clarifying meads, however, are giving them sufficient time for the yeast to finish their work and dropping the temperature 5-10 degrees. I use a spare fridge (set as warm as possible) for about 2 weeks, reracking and adding additional gelatin if neccessary.

Also, if you want a sparkling mead/cider/what-have-you, you don't want to completely clear your brew. You'll need to leave some of the yeast behind to ferment in the bottles and then trust time and cool temperatures to do the rest. Pour carefully in this case so you don't disturb the sediments!

Joyce Miller