Beyond the Brew: Clever Repurposing of Spent Coffee Grounds and Tea Leaves

Question: How can I repurpose stale coffee grounds or tea leaves for a different home use?

The satisfying ritual of a morning coffee or a calming cup of tea often leaves behind a familiar residue: spent coffee grounds and tea leaves. Far from being mere waste, these organic materials are brimming with potential for a second life around the home [2, 6, 7].

Nourishing Your Garden

One of the most celebrated uses for spent coffee grounds is as a natural amendment for gardens. Their composition, rich in nitrogen, potassium, and phosphorus, makes them a valuable addition to compost piles, accelerating decomposition [2]. When directly applied to soil, they can improve drainage and aeration, while their acidity can benefit acid-loving plants like blueberries, rhododendrons, and azaleas [2]. It’s worth noting that different coffee species can have varying chemical compositions; for instance, Coffea arabica tends to have a lower pH than Coffea canephora co-products [3]. Similarly, used tea leaves, particularly those from black tea, contain beneficial compounds that can enrich garden soil [1]. While specific pH ranges for tea leaves are not detailed, their organic nature generally supports plant health.

Natural Cleaning and Deodorizing

The abrasive texture of coffee grounds makes them surprisingly effective for tackling stubborn grime in the kitchen. They can be used to scrub pots, pans, and sinks, offering a gentle yet effective alternative to harsh chemical cleaners. Furthermore, coffee grounds are renowned for their deodorizing properties. Placing a small bowl of dried coffee grounds in the refrigerator or near a lingering odor can help absorb and neutralize unpleasant smells. The porous nature of the grounds allows them to trap odor molecules [6, 7].

Creative Crafting and Beyond

The utility of spent coffee grounds extends into the realm of creative expression. Researchers have explored their potential in creating biocomposites with wheat flour for biodegradable materials [2]. On a simpler, domestic scale, dried grounds can be incorporated into homemade soaps, adding a subtle exfoliating texture and a rich aroma. Similarly, dried tea leaves can be used as a natural dye for fabrics, producing soft, earthy tones. The residual oils and compounds within coffee grounds have also been investigated for their potential to yield bioactive compounds through processes like ultrasonication [6] or extraction using hydrodynamic cavitation [7].

While the extraction of specific compounds like chlorogenic acid is an area of active research [8], the broader application of these materials in DIY projects leverages their inherent physical and chemical properties. Even the froth from espresso, known as crema, is a complex interplay of proteins and lipids, highlighting the nuanced composition of coffee waste [1].

In conclusion, the journey of coffee grounds and tea leaves doesn’t end with their initial use. By understanding their composition and properties, we can unlock a multitude of practical and creative applications, transforming common kitchen waste into valuable resources for a more sustainable and enriched home environment.

References

[1] — Ernesto Illy, Luciano Navarini — Neglected Food Bubbles: The Espresso Coffee Foam. — 2011-Sep — https://pubmed.ncbi.nlm.nih.gov/21892345/ [2] — Magdalena Zdanowicz, Marta Rokosa, Magdalena Pieczykolan, Adrian Krzysztof Antosik, Katarzyna Skórczewska — Biocomposites Based on Wheat Flour with Urea-Based Eutectic Plasticizer and Spent Coffee Grounds: Preparation, Physicochemical Characterization, and Study of Their Influence on Plant Growth. — 2024-Mar-06 — https://pubmed.ncbi.nlm.nih.gov/38473683/ [3] — Katarína Poláková, Alica Bobková, Alžbeta Demianová, Marek Bobko, Judita Lidiková, Lukáš Jurčaga, Ľubomír Belej, Andrea Mesárošová, Melina Korčok, Tomáš Tóth — Quality Attributes and Sensory Acceptance of Different Botanical Coffee Co-Products. — 2023-Jul-11 — https://pubmed.ncbi.nlm.nih.gov/37509767/ [4] — Rongsuo Hu, Fei Xu, Liyan Zhao, Wenjiang Dong, Xingyuan Xiao, Xiao Chen — Comparative Evaluation of Flavor and Sensory Quality of Coffee Pulp Wines. — 2024-Jun-27 — https://pubmed.ncbi.nlm.nih.gov/38999011/ [5] — Faguang Hu, Haohao Yu, Xingfei Fu, Zhongxian Li, Wenjiang Dong, Guiping Li, Yanan Li, Yaqi Li, Bingqing Qu, Xiaofei Bi — Characterization of volatile compounds and microbial diversity of Arabica coffee in honey processing method based on different mucilage retention treatments. — 2025-Jan — https://pubmed.ncbi.nlm.nih.gov/39974542/ [6] — Jaquellyne B M D Silva, Mayara T P Paiva, Henrique F Fuzinato, Nathalia Silvestre, Marta T Benassi, Suzana Mali — An Ultrasonication-Assisted Green Process for Simultaneous Production of a Bioactive Compound-Rich Extract and a Multifunctional Fibrous Ingredient from Spent Coffee Grounds. — 2025-Jul-25 — https://pubmed.ncbi.nlm.nih.gov/40807293/ [7] — Hitoshi Soyama, Kousuke Hiromori, Naomi Shibasaki-Kitakawa — Simultaneous extraction of caffeic acid and production of cellulose microfibrils from coffee grounds using hydrodynamic cavitation in a Venturi tube. — 2025-Jul — https://pubmed.ncbi.nlm.nih.gov/40288159/ [8] — Krystyna Pyrzynska — Spent Coffee Grounds as a Source of Chlorogenic Acid. — 2025-Jan-30 — https://pubmed.ncbi.nlm.nih.gov/39942717/