Can tea go bad if left out? (plus 5 tips)

In this article, we will answer the question “Can brewed tea go bad If left out?”, and what is the shelf life of tea?

Can tea go bad If left out?

Yes, tea can go bad If left out. This happens because brewed tea is low acidic and rich in nutrients, which favors microbial growth. 

The deterioration process will be much faster if the tea contains highly perishable ingredients like milk or cream. If you used cold or room temperature water to make tea, it will also last less than a hot beverage.

The sensory quality of brewed tea will also decline over time [1]. Moreover, the compounds related to the health-promoting effects of tea can be significantly reduced, as they also experience degradation reactions. 

Komes and others [2] stated that after 24 hours of brewing, when stored at room temperature, a tea undergoes significant changes in antioxidant content and power, so we recommend you drink your tea just after its preparation. 

How to know if tea has gone bad?

To know if the tea has gone bad, go through this checklist: 

• The tea must not give off an acidic or strange smell, this indicates microbial growth.

• The tea must not present any cloudy appearance or floating particles, this can be a sign of mold development.

• The color should be the same or quite similar to that of the freshly prepared tea, any darker or clearer. Color change means oxidation/degradation of tea compounds, which means reduced flavor and benefits.

If you decide to store and consume any old brew: 

• Whenever it is hot or cold brewed, store it in the fridge, this will help keep the flavor and delay microbial and chemical changes. Holding in sealed flasks improves the protection effect by reducing contact with air.

• If it smells and looks fine, reheat it to at least 190 °F (88 °C) to kill the microbes and ensure safety. 

What are the factors affecting the shelf life of tea?

The factors influencing the shelf life of tea are the type of manufacturing process, type of packaging, and home storage conditions. 

• Manufacturing process: tea can be divided into unfermented (green tea), fermented/oxidized (white, oolong, or black tea). The more fermented/oxidized and unbroken the leaves are, the longer their shelf life. 

Therefore, green tea tends to hold the shortest shelf life; black tea, the most ferments among them, the longer [3]. 

• Type of package: Tea in bags tends to last longer because their pack materials protect the tea leaves from environmental humidity and contamination (for example attack of insects) [3].

 Loose leaves last less compared to tea in bags because they are more exposed to environmental conditions [3].  

• Home storage conditions: at home, tea should always be stored in a clean, cool, dry place, and protected from direct air and sunlight exposure.  

Tea leaves are highly hygroscopic, which means that if not adequately stored they will absorb moisture quickly from the ambient air, favoring microbial growth [3]. 

Air and sunlight can interact with the aroma and health-related compounds of tea, damaging them. Excessive heat can also promote their degradation [4]. 

What is the shelf life of tea?

The shelf-life of tea is of two years [1].  This is because tea leaves undergo chemical changes over time, losing aroma and antioxidant compounds (those that may benefit health) [1,5]. 

Thus, even if your tea looks pretty good, its flavor and chemical composition may have been significantly modified. Importantly, appropriate storage conditions must be used for this shelf life to be achieved. 

To know if your tea leaves have gone, observe its appearance and feel its smell: tea should not present molds, which can show a cotton-like appearance; it should smell like the day you bought it, otherwise it can be oxidized.    

How to ensure the maximum shelf life of tea?

To ensure the maximum shelf life of tea: 

• Always store your tea in a cool place or at room temperature. Keep it away from the stovetop and sunlight. 

• Keep your tea in a sealed package or an airtight container. Do not let it come in contact with the air frequently. Air will remove the volatile compounds of tea and deprive it of its aroma and flavor.

• Keep your tea container in a dark place preferably in a cabin.

• Do not let water get into your tea pack. Avoid using wet spoons to take tea.

• Only store the tea in the fridge or freezer if you are not going to use it for a long time after the purchase. The container or pack to store it in the fridge or freezer should be vacuum packed.

Conclusion 

In this article, we answered the question “Can tea go bad If left out?”, and what is the shelf-life of tea?

Citations 

 1. Sun L, Dong X, Ren Y, Agarwal M, Ren A, Ding Z. Profiling Real-Time Aroma from Green Tea Infusion during Brewing. Foods. 2022; 11: 684. 

2. Pastoriza S, Pérez-Burillo S, Rufián-Henares JA. How brewing parameters affect the healthy profile of tea. Curr Opin Food Sci. 2017; 14: 7-12. 

3. Motarjemi Y, editor. Encyclopedia of Food Safety. Waltham: Academic Press; 2014, pp. 371-383.

4. Guimarães R, Barreira JCM, Barros L, Carvalho AM, Ferreira ICFR. Effects of oral dosage form and storage period on the antioxidant properties of four species used in traditional herbal medicine. Phytotherapy Research. 2011;25(4):484-92.

5. Dai Q, Liu S, Jiang Y, Gao J, Jin H, Zhang Y, Zhang Z, Xia T. Recommended storage temperature for green tea based on sensory quality. J Food Sci and Tech. 2019; 56(9): 4333-48.