tea bag in a cup of hot water

Tea Bag Science – Dunking vs. Steeping

Nothing better on a cold day: a warm cup of tea. But I’m an avid tea drinker, drinking tea all through the day, not only cold days. Also, I’m a Dutch tea drinker (based on various encounters with non-Dutch people who were amazed by my/our tea making procedure). A Dutch tea drinker, in my experience, is someone who takes a tea bag and only puts it in their cup or pot for a few minutes or even seconds. No 30-minute long steeping. No dark bitter teas. No, we prefer a nice light tea, not too bitter (as opposed to the British who seem to prefer theirs black and bitter).

Also, I tend to be impatient once in a while. So, I dunk my tea bag up and down thinking this will make my tea faster. But while doing so again one day I wondered: “Is dunking my tea bag actually going to give me my tea faster?” And if so, is it of a better or worse quality than the slowly steeped version?

The investigation that followed quickly led me into food chemistry territory and extraction science. It led me past dozens of molecules and hopefully gives me the answer to my question!

Tea & Extraction

To answer my question about dunking vs steeping tea we have to start with some basic tea science. Tea is made from tea leaves which are dried and processed in various different ways to make the different tea types (e.g. black, green and white) and flavours. Once the tea has been processed and packaged it is a simple bag with dry tea leaves, ready for tea making.

When you make tea you submerge your tea leaves in hot (boiling) water, never in cold. This is where the extraction process starts. Components in the tea leaves will start dissolving in water at this point. This is the critical process when it comes to comparing dunking vs steeping your tea bag.

tea bag steeping in a hot cup of water

What’s in tea?

But first, let’s zoom out a little. What’s actually in tea, in other words, which molecules can seep out of the tea leaves into your boiling water? In the tea making process only those molecules dissolve in water which can actually dissolve in water. But tea contains a lot of different molecules and not all of these molecules dissolve well in water!

The most common molecule groups in your liquid tea are: polyphenols, caffeine (and related molecules), proteins & amino acids, carbohydrates, organic acids, pigments and vitamins & minerals. These all dissolve in water pretty well. There are however also starches such as cellulose which do not dissolve in water as well.

Polyphenols are the most prevalent molecules in tea which is why they are commonly discussed in tea chemistry articles. If you’re interested in doing a deep dive in the topic it’s worthwhile reading the 1997 article from M. Harbowy & D. Balentine, Tea Chemistry, published in Critical reviews in plant science.

Rates of extraction

So now that we’ve got an overview of the molecules in tea which will be extracted when you’re making tea, we will look into the rate with which this happens. Some molecules dissolve in water very fast whereas others take more time. If you only steep your tea for 3 minutes, it might be that there are a lot more fast dissolving molecules than slow ones! Whereas if you steep your tea for 30 minutes, probably all of the molecules will have had ample time to dissolve. In other words, that could potentially give your tea a very different flavour.

Unfortunately, I do not know how fast the different molecules all dissolve. There isn’t a concise overview comparing all of them (I was able to find just one piece of research looking into this.). One reason for that is that the rate depends on a lot of different factors such as temperature of the water, pH (acidity) of the water, the presence of other minerals, etc. So it’s hard to quantify the difference a 3 vs 30 minutes steep will give as well as the difference between a quick dunk vs a slow steep.

From my own personal experience I am guessing that colours (pigments) dissolve faster than certain bitter components. Reason for this hypothesis? I, as a Dutch person, tend to re-use my tea bag for 2-3 cups of tea. Since not all flavours have been extracted by the first steep and dunk, there is still more than enough in the tea bag for a next delicious cup. But, what I tend to notice it that the last cup tends to be lighter in colour but slightly more bitter. This especially goes up for green teas.

Steeping or dunking?

Ok, so can we say something more about steeping and dunking now? We know that the rates of extraction are different for different molecules and that tea contains a lot of different molecules. And that we actually don’t really know a lot about this except for some personal experience. But then how does this relate to dunking or steeping?

First of all, dunking making the molecules move, there will be convective flow. If there is a flow of molecules they tend to spread around more easily. But do they also dissolve faster? My first thought would be yes. Since they spread out more the concentration is more evenly spread. We also know that if the concentration of certain molecules is high the movement of more molecules to that area can be slower. So, by spreading the molecules around it might speed up the extraction of other molecules?

The proof is in the pudding I would say here. I am pretty sure that if I dunk my tea bad it colours darker more quickyl than when I leave it to steep. But, maybe the colours just dissolve very easily, whereas other components do not!

I found several articles claiming that dunking vs. steeping doesn’t have any effect. But in the end most of them seemed to refer to this one article. So not sure whether that’s enough proof just yet. Also, it seems to refer to making ‘British tea’. In other words, the super dark and bitter version where you want to extract everything. If indeed you have to wait for those slower molecules, there might not be much of a difference.

However, ‘Dutch’ tea making clearly doesn’t strive to extract all molecules from the tea. So it could well be causing a difference?!

My conclusion

I’m not a 100% sure what’s best. Personally, I’ll probably keep dunking my tea bag whenever I’m in a hurry. It feels faster for sure!

tea steeping in a cup of water

What’s your personal experience? Or do you have some extraction chemistry to bring into the game here?

Sources

Another great article about in-depth tea chemistry is: Black tea: chemical analysis & stability. Or read more on this website fully dedicated to tea.

 

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