Teacology

Tea, with an Ecological Approach

Brewing Iced Tea to Minimize Energy Usage

3 Comments

This post is an expanded, follow-up post to my original post Energy Saving Tips for Making Iced Tea.  I also expounded these same ideas in RateTea’s article on iced tea.

The hottest part of summer is approaching, and I’ve already brewed up my several first batches of iced tea.  As subscribers to my old blog and readers of the articles on RateTea will likely know, I’m a die-hard advocate of brewing your own iced tea, ideally from loose-leaf, rather than purchasing pre-brewed bottled or “ready to drink” teas.  But here I’m going to take for granted that people are interested in making their own iced tea at home, and I’m going to focus on how to do so in a way that uses the least energy.  I brew a lot of iced tea: two batches a day of four cups each in the hottest part of the summer, so I’ve had an opportunity to experiment and develop a method that results in superior flavor but is fast, easy, and energy efficient.

At the end of the article, you’ll also find an explanation of how drinking iced tea, regardless of how you brew it, can help you further reduce your energy usage!

Why is minimizing energy usage important?

Energy efficiency is one issue that I care about a lot.  Most electricity in the U.S. in generated in ways that have numerous negative impacts on the environment: the burning of coal and natural gas releases both carbon dioxide, a greenhouse gas, and various pollutants into the atmosphere.  Coal burning for electricity generation is a major source of mercury, which contaminates seafood like tuna, making it unsafe for consumption.  I use EDF’s Seafood Selector and it concerns me how many types of seafood are contaminated with unsafe levels of mercury.  Even cleaner forms of energy like hydro, wind, and solar still have some negative impacts on the environment.

A coal fired plant, with big smokestacks, and a lake and beach in the foreground

Although renewable energy production in the U.S. has been increasing, about half [source] of the electricity here still comes from coal-fired plants like this one in Calumet Park.  Public Domain Photo by the US EPA, taken from Wikimedia Commons.

Global climate change, which is directly related to energy usage, poses a direct threat to numerous countries, through many different mechanisms.  Sea level rise threatens low-lying areas as diverse as Florida, New Jersey, and Bangladesh, and the changing climate threatens both ecosystems and agricultural development.  Climate change is already negatively impacting the industry that produces tea and herbs.  For example, tea production in more arid regions of the world like Kenya is threatened by periods of prolonged drought, and rooibos production in South Africa has also faced threats from climate change.  The Ethical Tea Partnership has a page on the negative impacts of climate change on the tea industry.

In addition to the long-term benefits of reducing your energy usage, you will see an immediate benefit as well: saving money on your electric bill.  I think people with a broad range of views on political and environmental issues can agree that reducing energy usage is a good thing.

How does brewing iced tea use energy?  How can we reduce these uses?

Making your own fresh-brewed iced tea uses energy in two ways: heating and cooling.  In order to minimize your energy usage when making up a batch of iced tea, you need to minimize both of these processes.  People who have central air or an air-conditioned kitchen will benefit doubly from reducing heating, because any waste heat generated by your heating method will need to be pumped out of your living space by the air conditioner, at additional cost.

Here is my method:

  1. Brew a very small amount of concentrated tea with hot water.  This minimizes the energy used for heating.  You can try cold brewing (steeping the tea directly in cold water), but this doesn’t work well with all types of tea.
  2. Let the brewed tea cool to room temperature.  I do this quickly by placing the tea in a closed jar, and setting it in a pot which I fill with cold water from the tap.  This chills the water to the temperature of the cold water in your home, without using any energy for cooling, thus minimizing your cooling costs.
  3. Dilute the tea to taste with cold or room temperature water.
  4. Chill the tea or, for quick results, pour over ice.

For the fastest results, you can skip step 2 and condense steps 3 and 4 by filling a glass, jar, or pitcher with ice and pouring the hot tea on top of the ice, adding any cold water if necessary for additional volume.

Below is an illustration of this process.  Here I steeped Ahmad Tea’s Ceylon, one of my favorite teas for use as iced tea.  Note the dark, concentrated color in the lower-left.  Here, I steeped this tea at quadruple strength (four teaspoons of leaf in one cup of water), because I planned to make four cups.  The upper right panel shows the tea once it had been diluted to the proper strength.  I put this jar in the fridge to chill, but only after I poured myself one cup, pouring over ice (lower left) to produce the cup pictured in the lower right.  I used a kimchi jar, which I have found to be quite heat-resistant (and which I always have available, as I eat a lot of kimchi).  It’s important to take care with your choice of a glass vessel, as pouring hot liquids into generic glass can sometimes cause it to shatter.

Four photos showing concentrated iced tea, diluted iced tea, a glass of ice, and a glass of iced tea

An illustration of my process for making iced tea

There are a few other supplemental tips that you can use to further minimize your energy usage.

  • Consider how you are heating the water:
    • Microwaves are one of the worst options, being considerably less efficient than a typical electric stove.  If you’re not convinced, read this comparison in Home Energy Magazine.  Home Energy Magazine, by the way, is a great place for finding more energy-saving tips.
    • If you have a gas stove, unless your electricity comes from a clean, sustainable source, using a gas stove is better than anything with an electric element, because a gas stove converts 100% of stored energy to heat, whereas when using electricity, only a small portion of the stored energy in the fuel used to generate the electricity is converted to electricity–most is released as waste heat at the point of generation, and more is lost through wires in transmission.
    • If you live in a state with electric choice (like Pennsylvania or Texas), choose a sustainable electricity generator like Green Mountain Energy, to minimize the environmental impact of your electricity usage.
  • Choose a cool day or time of day (early morning is typically the coolest time of day) to make large batches of ice or chill large batches of water or iced tea.  Refridgerators and freezers need to work harder on hot days.  It doesn’t matter if you have central air or if the refridgerator is in a room directly affected by outdoor temperature–any of the heat your fridge pumps out into your home will need to be pumped out again by the air conditioner, which has to work harder when it’s hot outdoors.
  • Follow general best practices for refrigeration.  Try to keep your fridge reasonably full; if you don’t have stuff to put in it, you can keep it full of jugs of water and put bags of ice in the freezer.  Make sure the coils on the back of your fridge are clean, and that the refrigerator has enough space behind it to allow good air circulation.  Check the seal on the door to make sure it is holding the air in.

Energy usage is a surprisingly deep topic, in that there is virtually always more you can do to reduce your energy usage.  Some energy-saving tips are easier to implement or more practical than others, but I hope that you have at least found some tips above which will help you to prepare iced tea in an environmentally-sound manner that also results in a superior-tasting batch of tea to drink.

One of the reasons I have gone so deep into this topic here is that I think the ideas presented here have broad applicability.  In the global scheme of things, the amount of energy used in making iced tea is tiny compared to the amount of energy consumed by numerous other things.  But the knowledge and ways of thinking that can be used to conserve energy are universal.  Processes that generate heat and cooling are at the heart of energy usage in homes, businesses, and industry, and  the ideas communicated here are universal and can be applied to far more than just the making of a cup or pitcher of iced tea.

Weighing Conservation of Water vs. Electricity

There are some parts of the U.S. and parts of the world, where water scarcity is a more pressing issue than energy usage.  Where I live, there is little need for water conservation, and the negative impacts of electricity use far outweigh the extra water used.  The same is true of costs: typical electricity usage tends to be much more costly in financial terms than typical water usage, at the rates charged by most municipal governments in the U.S.  But there are a few places where these rules do not completely hold.  In the southwestern U.S., water use has major negative environmental impacts, such as destroying the ecosystem in the Colorado river delta.  And in rural areas, people who drink well water often need to use electricity to pump their water, so conserving water is important for conserving electricity.

Lake mead, with dry hillsides and dark blue water

Lake mead, used as a reservoir for cities in the Southwest.  This water would have naturally flowed into the Colorado river delta, supporting a rich delta ecosystem, and an estuarine ecosystem in the Gulf of California. Photo by Rick Pecoraro, licensed under CC BY 2.0.

The method I described above uses additional water at one step, using a bath of cold water from the tap to cool down the jar of hot tea.  If you live in an area where water is scarce, or where you need to use electricity to pump your water, you can skip this step and opt for a slower cool-down to room temperature.

One Final Note: Cold Drinks Can Reduce the Need for Air Conditioning

There is an additional way that iced tea and other cold beverages, regardless of how you prepare them, can reduce your home energy usage.  If you keep your home air conditioned, continually drinking iced tea during the hottest hours can help your body to stay cool, enabling you to feel comfortable in a warmer environment.  This can allow you to set your thermostat higher in the hot weather, while still being comfortable.

What do you think?

  • How do you brew iced tea?  Do you already use any of these tips here?  Did you find any new pointers that you want to try out?
  • Have you had much success with cold-brewing?  Do you have any advice for people who wish to attempt cold-brewing?
  • How much do you think about energy saving in general?  Have you found some of the ideas and concepts in this post helpful in other aspects of your life, in terms of providing things you can do that can reduce your energy usage?
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Author: Alex Zorach (teacology)

I am the founder and editor of RateTea, and am also a co-founder at Why This Way. I am committed to sustainability in every aspect of my life. I like describing my approach to life as "ecological" because it is both scientific and holistic.

3 thoughts on “Brewing Iced Tea to Minimize Energy Usage

  1. A thoughtful discussion! I hadn’t considered cold brewing as a means of conserving energy.

  2. Why not sun tea? You just leave the tea in the sun and let it brew for a while.
    I’ve also heard sun tea and cold-brewing tea makes for better tasting iced tea anyway.

    • I’ve seen several reputable sources, including Colorado State University Extension’s SafeFood network, state that making sun tea is not safe. In particular, they advise to “Never maintain brewed tea for more than eight hours at room temperature”. They advocate for either cold-brewing in the refrigerator, or brewing quickly and then chilling. I’ve seen numerous other sources also verifying this. The issue seems to be prolonged, slow brewing of tea at warm temperatures. Cold temperatures inhibit bacteria growth, and very hot temperatures kill the bacteria, but warm temperatures, especially when sustained for a long period of time, encourage bacterial growth.

      I’m not someone who is overly paranoid about bacteria, but there are enough strong warnings from reputable sources in this case that it’s something that I’d be cautious about.

      It could be that the risks are overstated and that there’s no real risk here. This seems possible to me, just based on my knowledge of biology, especially if there is no sugar or other food for the bacteria–as tea has little that bacteria can eat as fuel, and a lot of chemicals that inhibit its growth (not just caffeine). TeaGeek has issued a post, Sun Tea Winner (Plus a Rant About Information Drift), which critiques this information. I tend to trust TeaGeek (Michael J. Coffee) as a source of information…he has consistently demonstrated very high standards of truthfulness, careful and thorough research, and accurate reasoning and critical thinking skills, so I’d be inclined to trust his take on this issue.

      But for now, I will stick to either hot brewing or cold brewing, and avoid the long-term brewing of tea at warm temperatures. I think I will also ask one of my friends who is a Ph.D./M.D. and whose research and reasoning skills I trust greatly, and see what she has to say about this issue too. Perhaps I can publish a follow-up post on this question.

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