Don Mei: Hey teaheads! This is Don from Mei Leaf. In this video: Ice-brewed versus cold-brewed
tea. It's a hot, muggy summer's day here in London, and I'm craving something cool and
refreshing, so I thought I would show you "ice brewing" - a.k.a "Kori Dashi - and we're
going to be doing a head-to-head to see if it tastes better than cold-brewed tea. For
those of you who are interested in cold brewing I've done a whole video about cold-brewed
tea, but essentially, you're taking leaf and you're brewing it in cold water - sort of
5 to 10 degree Celsius [40 to 50 degrees Fahrenheit]. But with Kuri Dashi - or "ice brew" - you're
taking leaf, you're mixing it with ice, and you're allowing the ice to melt and brew in
that melted ice water. So [it's] ultra-cold brewing. Now, we know that temperature affects
the flavor of tea, because there are many different compounds in tea that contribute
to the flavor and effects of tea, and they will all extract at different rates according
to temperature and time. Some of these compounds extract very readily at low temperatures,
[whereas] others require a lot more heat, or a very long, extended period of time. For
example, catechins - the antioxidants in green tea, which contribute to the health benefits,
but also contribute to the bitter notes in green tea - they require relatively high temperatures
in order to get extracted quickly. So therefore, we always advise clients to brew your green
tea at slightly lower temperatures - sort of 70, 80, [or] 85 degrees Celsius [160-185
Fahrenheit] - because the you can control - you can attenuate that bitterness, and make
sure that the taste is exactly as you want. If you brew the green tea with boiling hot
water then you have no control. It will extract all of those catechins out very quickly, and
you're more likely to have a bitter brew. Similarly, caffeine. Supposedly - and I have
not tested this out - but supposedly, caffeine requires hotter temperature, and therefore
when you are cold-brewing you are maybe extracting less caffeine. However, because you are cold-brewing
for extended periods of time chances are you are getting a fair hit of caffeine. Again,
[we] haven't tested that out. That's the subject for another video. Today, what we want to
do is figure out the taste difference between "ice brew" -"Kuri Dashi" style tea - and cold-brew
tea. So what I have here is Fuka Mushi Sen Cha. The reason why I'm using Fuka Mushi Sen
Cha is because, first of all, ice-brewing - or Kuri Dashi - is a Japanese method of
brewing green teas. And secondly, because it's a deep-steamed tea the leaves are broken
up. That means that there's more surface area for extraction, and I'm not going to have
to wait too long to drink my tea. Right. Let's get started and show you how we're gonna do
this... We've got 4.5 grams of Fuka Mushi Sen Cha, and we're gonna be brewing in 100
[milliliters] of water. So essentially, we're Gong Fu brewing cold-brewed style. So we really
can get the taste difference between the Kuri Dashi and the cold-brewed. So what I'm gonna
be doing is I'm gonna be brewing this one in ice for an hour-and-a-half, at room temperature.
And this one here I'm gonna be brewing for 45 minutes in 100 [milliliters] of cold water.
[We've] measured the temperature of the water at 20 degrees Celsius coming out of the tap,
and immediately it's going to go into the fridge. So it's going to be bringing it down
to 5 degrees. It's gonna be very difficult to standardize this, because you've got various
different parameters at play here, but we're hoping that by the end of the hour-and-a-half,
for this one, and 45 minutes, for this one, we're gonna have a similar strength brew,
and a similar temperature brew. So let me pour this in here. [POURING ICE] We've got
92 grams of ice here. The reason why I'm using 92 grams is because ice is less dense than
water. That's what makes water so magical, is that in its solid form of ice it's less
dense, which is why the ice cubes float. And the density of ice is around 0.92 grams per
cubic centimeter, and therefore 100 [milliliters] of water is equivalent to about 92 grams of
ice. We're gonna put this away, [and] we're gonna cover it in cling film so that it can't
absorb any aromas, and we're gonna be leaving it at room temperature for 45 minutes. After
45 minutes were gonna add the 100 [milliliters] of water into this one, again [covering] it
in cling film [and putting] it in the fridge. [Then] we're gonna wait another 45 minutes,
and then by the end of it hopefully we've got two teas to test out. It's important to
note that this style of brewing - the Kuri Dashi style of brewing - is very different
from if you're cold-brewing on a hot day outdoors, and you just want to use ice to control the
temperature so that the ambient temperature of - I don't know, 20, 30, [or] maybe even
higher - degrees Celsius [60 - 85 Fahrenheit] is not raising the temperature of your water
too high, and you're just using ice to keep the cold brew. That's sort of a different
technique. This is strict ice-brewing at room temperature, indoors, at 20 degrees [Celsius],
and by the time it's finished it should still be cool, like the fridge temperature, and
we should be able to get a like-for-like match in terms of strength. Let's give it a try...
While that tea is brewing let's quickly talk about the ice, because, of course, the quality
of the ice is very, very important if you are doing Kuri Dashi brewing. It's very important
to note that the ice that I'm using for this experiment is made from the same water that
I'm using for cold-brewing. So we're trying to standardize the water. Of course, the quality
of the water that is used to make the ice is going to have a huge impact on the flavor
of the tea. But what I have here is the water - which is tap water which has been filtered
and Granderized - and here I have the ice that has been made from that water, and it's
been remelted into water. So what I want to find out, before we taste the tea, is if the
act of freezing the water actually changes the flavor, or the quality, of the water.
So let's give this a taste. This is the tap water. [SIPS TEA] [It's a] very, very transparent
taste. [There's a] slight sweetness. Now some people say that water should have no taste.
I disagree. I think water has a taste, but certainly, the more transparent the flavor
the more it feels like a sort of neutral, "It tastes more like water." - if you know
what I mean - in its tastelessness. [SIPS TEA] It's soft. It's a little bit drying towards
the end, and I'm getting a slight sweetness, but it's relatively transparent. Now, let's
taste this one here. [SIPS TEA] Immediately, it's very, very different. I'm getting a sort
of [flavor] there. It tastes slightly flat, [and] it has a drier texture. And this is
really interesting, and one of the reasons why, for me, [I question] ice-brewing. Because
the quality of the water seems to deteriorate when you freeze it and then melt it again.
That's just my impression, and my opinion. But do this experiment yourself. Take the
water, freeze it, and melt it, and then see if you taste the difference. Now what's happening
here? Well, of course, one of the things that you've got to try to avoid is aromas in the
freezer affecting the flavor of the ice - in other words, the water picking up aromas in
the freezer. Which is why when I freeze this ice I make sure that we're freezing it and
we're wrapping it in cling film again, to stop odors from going into the ice while it
is melting. [SIPS TEA] But also, if you look at this ice you can see that it's very opaque.
It's got an opaque, cloudy, almost white quality. What's happening here is when the ice freezes,
and the crystals form, they force dissolved gasses in the water out, and those dissolved
gasses become trapped in the ice cube, and that makes it opaque. If you go to one of
those fancy cocktail bars you'll find this beautiful, crystal-clear ice - or if you look,
in nature, at stalactites, you see beautiful, crystal-clear ice. What's happening there
is, because the ice is freezing at a relatively high temperature - in other words, just below
freezing point - the gasses that are being forced out actually leave the water, and so
the end result - the frozen liquid - is clear. But when you're freezing in a freezer it's
freezing relatively quickly, and therefore the gas is being trapped. Now, does that mean
that once this ice has been melted there is less [dissolved gasses] in the ice? Some people
say, "Yes." Other people say the opposite. [They] say [that] cooler temperature, colder
liquids, have higher solubility for gas, and therefore you're going to have higher levels
of CO2 and oxygen dissolved in the water. I don't know. I can't do those tests myself.
But certainly, what I can tell you is that melted ice tastes different from water, even
if it's made from the same water and it's frozen very, very carefully, and wrapped up
in cling film. And that is gonna definitely come into play when we taste our teas... Here
they are. The teas have been brewed. I had to extend the time for the Kuri Dashi ice-brewing
to two hours, and the cold brew was brewed in the fridge for 45 minutes. I realize that
all of these parameters are very varied, and it depends on the size and shape of your ice
cubes. There's lots of variations here, and we are just sort of experimenting. If you've
got any ideas for how we can improve these experiments then please do tell us. Here you
go. Take a look at the color of the liquors here. [HOLDING UP GLASSES] You can see [that]
the volume is pretty much the same, but the Kuri Dashi -- Wow! Look at that color. [It's]
vibrant, vibrant green. This one here - the cold brew - is a little bit more yellow, compared
to the iced-brewed tea. Certainly, if you're going for looks then the Kuri Dashi ice brewing
Fuka Mushi Sen Cha is the winner for sure. But it's all about taste. So let's put some
of this cold brew in. [POURING TEA] [It's got a] lovely, thick, gelatinous texture here.
[POURING TEA] And here is the Kuri Dashi. Again, the color difference between these
is quite remarkable. I'm gonna start with [the] Kori Dashi - the ice brewed. Cheers
everybody. [SIPS TEA] I allowed the Kuri Dashi to come a little bit back to the same temperature
as this. After the [ice had melted] it was about 3 degrees [Celsius]. This was obviously
5 degrees in the fridge, but they're about the same temperature. [SIPS TEA] Mmm! [It's
a] very, very thick and dense texture. The taste [is] very, very fresh, very, very bright,
[with] zero bitterness, [and] lots of zing on the sides of my tongue. [SIPS TEA] However,
I'm searching a little bit for that body and depth in the finish. The finish is lovely.
I'm getting a little bit of that lemony usu, [wild] strawberry note. [It's] very, very
nice [and] delicious. I love it, but let's see how it compares to the cold-brewed in
the fridge. [SIPS TEA] Texture [is] the same. [SIPS TEA] But [the] taste is very, very different.
It's fresh, [and] it's bright, but you're getting more umami, more savory note, [and]
a little bit more bite in there. [There's] a little bit more bitterness. So this one
- the Kuri Dashi; the ice brew - is bright, light, and has very little bitterness, and
very little astringency. Whereas the cold brew [SIPS TEA] has just got a bit more depth
of body, a bit more umami, and definitely a little bit more bite. So it is down to preference.
If you ask me which I prefer, [SIPS TEA] I would say I prefer the cold brew. And that's
not just because of the extra body in the cold-brew. It's not because I like a little
bit of bite in my teas. But also, with the Kuri Dashi I'm tasting that melted ice-water
taste. It's kind of got a stale taste to it, [SIPS TEA] and I only pick it up now once
I'm comparing it back to back. But there's that sort of water that's just been a little
bit left stagnant - a bit stale - that melted ice cube taste. I'm sure a lot of you understand
what I mean. When you taste the melted ice cube water it just has a certain sort of flatness,
and deadness, to the taste [POURING TEA], compared to the cold brew [SIPS TEA] which
doesn't have any of that. It's bright, [and] it's dancing. Yes, it has more body. Yes,
it has more bitterness, and if you're looking for zero bitterness than you may want to go
for sort of a hybrid version of this, where you're taking cold-brew water and you're adding
a little bit of ice to just bring it down to temperature so that that period of time
where it's at that sort of 10 to 20 degrees [Celsius] temperature - from coming straight
out of the tap to going into the fridge - that temperature range is gonna be pulling out
a little bit more of those catechins compared to the ultra-cold brewing. It is a matter
of taste, however I would say the key deciding factor for me is that slightly melted ice,
stale taste in the Kuri Dashi. Of course, this is all down to preference, [and] this
is all down to taste... Hold up! Hold up! It's the next day. [Here's] a quick update.
After finishing filming this video yesterday evening I turned off the camera and I felt
a bit dissatisfied, because I hadn't found for you the perfect way to brew this Fuka
Mushi Sen Cha cold. The ice-brew lacked a certain bite, and it had that weird, flat,
stale taste that comes from melted ice. On the other hand, the cold-brew version had
a bit too much bite, and it didn't have that ultra- bracing vibrancy that the ice-brewed
version had. So we spent last night trying to find the perfect way to brew this tea.
We went out [and] we bought different ice cubes, just in case it was my freezer that
was causing the problem. We worked until about midnight [to]1:00 AM yesterday, until we found
the "eureka moment" - that perfect way to not just brew this tea, but also serve it.
So I'm gonna be doing a video. That'll be next week's video. I highly encourage you
- if you're interested - to pick up a pack of this Fuka Mushi Sen Cha. I promise you
you won't regret it. I absolutely adore this drink that we created yesterday, and I'm so
excited to share it with you. But until then, check out our other videos, fire over any
questions, comments, or video ideas. Taste our teas, wherever you are in the world, by
browsing MeiLeaf.com, and if you're ever in London then come visit our teahouse in Camden.
Other than that, I'm Don from Mei Leaf. Thank you for being a part of the "revelation of
true tea". Stay away from those teabags, keep drinking the good stuff and spread the word,
because nobody deserves bad tea. Bye [WAVING].