Upcycle your coffee grounds into a homemade firelog

Nothing warms up the holiday season quite like a blazing fire. One environmentally conscious way to bring warmth to your home is by creating logs using upcycled coffee grounds. These coffee logs have been shown to burn hotter and longer than traditional wooden logs, do not require any felling of trees, and emit fewer greenhouse gases than burning traditional wooden logs. If that is not incentive enough, you can create them by using ingredients you already have in your home. Pre-used wax from old candles, leftover dried coffee grounds from your morning cup, and even reused take-out chopsticks from your evening food delivery combine to create your very own eco-friendly fireplace log.

What you will need

One 9 X 5 inch baking pan

Approximately 7.5 ounces of candle wax (or 2.5  12 X 1-inch pillar candles)

1 – 2 Cups of molasses

6 – 20 Heaping tablespoons of dry coffee grounds

Stirrer (an old whisk, paint stirrer or disposable chopsticks will do nicely)


1) Preheat your oven to 260F.

2) Combine molasses and candle wax in your bread pan. The amount of molasses used varies by reference recipe, with the consensus being to make sure you have a generous portion coating the bottom of your pan. I used a full 2 cups, and there was an excess of molasses. I believe 1.5 cups would be sufficient. The molasses helps to bind the log together.

put in oven.jpg

3) Heat the mixture for 30 minutes at 260F. At the same time place a separate metal tray containing your coffee grounds in the oven. This will ensure that any remaining moisture is removed from your coffee grounds. Once the wax is completely melted, remove the pan from the oven and make certain your coffee grounds are completely dry. Add the grounds to the mixture.


4) Mix in enough grounds to obtain a sludge-like consistency (see picture below). Depending on the type of wax, how much wax, and the amount of molasses you used the quantity of grounds needed will vary. I used 2 cups of molasses and 7.5 ounces of soy wax. Using a traditional tablespoon as my measuring device, I needed 20 heaping tablespoons of grounds. It is of the utmost importance that your grounds are completely dry and that your mixture is thoroughly and well blended with a glossy, sludge-like consistency before setting the log. Adjust the amount of grounds used to obtain this mold-able form.


5) Cover the pan with aluminum foil and press firmly on the top of your log. Remove the foil and freeze your log for at least one hour.

6) Once cooled, cut around the edges of the pan to remove the log. I used a sharp knife and then turned the pan over, firmly tapping the underside with a hammer. My log came out easily.


7) Once you have removed your log from the pan, it is ready to burn. Flip it over so that the “glossy side” is facing up and place it in your fireplace. You can use a fire starter or the kindling of your choice to ignite the log. This log burned for a little less than an hour, and the smoke was minimal, the house smelled amazing — like molasses coffee cookies.


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9 thoughts on “Upcycle your coffee grounds into a homemade firelog

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  1. Hi tried to make my own coffee logs but despite ensuring everything was melted and coffee grains mixed in to make the sludge mixture, I was left with a top film of wax, like it had separated. The log held together a bit but broke up too easily.

    Any ideas or tips for my next attempt? Thanks.


    1. Hi There!! Trial and error was definitely my friend when I constructed my own log 🙂 I found that it is imperative that the coffee grounds be completely dry before mixing. It is possible that excess liquid may be causing the separation. Also, the sludge-like consistency should be thick enough such that the log molds and sticks together easily. Depending on the type of wax used you may also need to up the number of coffee grounds. I did have some breakage when burning the log, but it continued to burn nicely, even though it split. I wish you luck in your next log endeavor!!! Should I remember any other helpful tips I will pass them on! XX


  2. I wonder if Karo corn syrup would work as well as molasses. I can’t see burning my coveted sorghum molasses in the fireplace. . .


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