Vacuum sealing and freshness

[Cha Nacho]

Hi all,

A quick question about vacuum sealing: does green tea (or other) lose freshness over time if it has been fully vacuum sealed?

Secondly will green tea, or other varieties, lose freshness if they are sealed in a vacuum package but do not have all of the air sucked out? (For example for most delicate greens that would get crushed by full vacuum sealing)

cheers

[olivierco]

A quick question about vacuum sealing: does green tea (or other) lose freshness over time if it has been fully vacuum sealed?

Yes, full vacuum is impossible to achieve (especially if you don't want the tealeaves to get crushed). Oxydation will slowly appear in the tealeaves anyway

Secondly will green tea, or other varieties, lose freshness if they are sealed in a vacuum package but do not have all of the air sucked out? (For example for most delicate greens that would get crushed by full vacuum sealing)

Yes, but if you fill the package with nitrogen or any inert gas, the tea will be fresh for a longer time.

[Chip]

+1 on all counts. I believe most Japanese greens are nitro flushed these days.

I have received some that are also vacuum packed, they were fukamushi so no real harm done.

I would not want to receive a high end asamushi that was vacuum sealed however.

[Cha Nacho]

Thanks for the replies, that's very interesting I didn't realise that the true vacuum does not remove all of the oxygen from the bag. So, whatever is left in there would slowly react with the tea leaves. I like having many varieties of tea, so this info is beneficial when thinking about the quantity to buy.

[Charles]

REGARDLESS of the form of packaging or storage the tea will age. Tea is a seasonal product so at some point you will be drinking a tea that is 11 or 12 months old, but there is no good reason to buy more tea than you can drink in a year.

[Kevangogh]

Vacuum packaged green teas should be flushed with nitrogen first, then vacuumed. That's how it's done with the few vacuum packaged green teas we sell.

[debunix]

I noticed a large drop off in sweetness of my first package of gyokuro kin by the end of the 2 oz package. I still haven't finished it, three months after opening it, although it took me a while to figure out what to do with it and to start drinking it several days a week. While I want to continue to drink it, I will probably always drink more oolongs and puerhs, so would like to know how to best preserve these vacuum packed teas after opening: seal a meal with a silica packet? refrigeration? do nothing, and accept that only half of each batch will really be pleasing?

So....what do you like to do for similar delicate teas that you drink slowly?

[Chip]

I noticed a large drop off in sweetness of my first package of gyokuro kin by the end of the 2 oz package. I still haven't finished it, three months after opening it, although it took me a while to figure out what to do with it and to start drinking it several days a week. While I want to continue to drink it, I will probably always drink more oolongs and puerhs, so would like to know how to best preserve these vacuum packed teas after opening: seal a meal with a silica packet? refrigeration? do nothing, and accept that only half of each batch will really be pleasing?

So....what do you like to do for similar delicate teas that you drink slowly?

It is generally recommended that you finish a Japanese tea within 30-60 days of opening. Gyokuro is often the exception to this rule ... I have had some open already for almost 6 months ... it actually improved the tea this time, not unheard of for gyokuro.

Perhaps your storage methods need some improvement? Care to share how you store your tea once open. Also is is more humid where you live? Very hot? Indoor climate can play a factor.

[debunix]

I live in Los Angeles, so generally my indoor environment is very dry. I also have no air conditioning, so indoor temps are will into the 80s in the summer.

The tea came in a heavy plastic pouch, with a ziploc seal used after breaking the initial seal on the pouch, and has been stored in a closed cabinet between infusions, with the silica pouch left in, sealed with the ziploc and as much air pressed out of the package as I can without crushing the tea.

A related question would be, are there any vendors who sell gyokuoros or senchas in well-sealed packages of 25-30 grams apiece?

My 56g package was from denstea, and the other vendors whose names I recognize from other forums sell in larger quantities.

[Chip]

BTW, welcome to the forum!

I see mostly 50-100 gram foil pouches of Gyokuro. O-Cha has a bunch. It does not make much economic sense to put them in smaller bags. I have seen single serve pouches however ... never tried them myself and they were quite expensive.

The pouch from Den's is foil lined and pretty decent for storage after opening. However the silica or whatever it is is likely not helping after the seal is broken on the bag.

Yeah, you might have a temp issue there. I am guessing that played a factor in its fading so fast. Sencha I try to use up in around 30 days after opening. Like I said, Gyokuro should last much longer after opening.

[debunix]

Yeah, you might have a temp issue there. I am guessing that played a factor in its fading so fast.

Maybe I should make it a winter specialty for now.

I was considering using some seal-a-meal pouches to re-seal portions of the package after opening, but don't have the capability to do nitrogen flushes before sealing them.

[teaisme]

some things I didn't see you mention to preserve freshness

-limiting the time you open the bag, quick in quick out
-storing 1/2 or 1/4 of tea in another container for the next few brews, while leaving the main bag untouched until it is time to refill (to limit number of times you open the bag)

As with other posters though, I think the main issue for you is temp. That just seems too hot.

[debunix]

Would Refrigeration be reasonable for the bulk of the unused tea, leaving some in a small well-sealed container for daily use?

I have already tried to avoid keeping the tea open and longer than necessary and removing as much air as I can easily do with each use.

[Tead Off]

Vacuum packaged green teas should be flushed with nitrogen first, then vacuumed. That's how it's done with the few vacuum packaged green teas we sell.

As an online store owner, how do you store your teas when you first purchase them? Do you keep them in bulk or do you package them as soon as possible?

From your experience, what kind of change do you see in a first flush tea when stored until winter? Do some teas benefit from a bit of ageing?

[Kevangogh]

We have an office and storage facility. The storage facility has a big refrigerator for all of the matcha. The loose leaf teas are packaged by the vendors for us in our own packaging and stored in specially sized bins. We don't package the teas ourselves at this stage, all of our vendors have facilities to do this so it's not necessary. Of course, I have watched them package the teas so I know how it's done, especially in regards to nitrogen. When a tea is vacuum packaged, at least in our case, the package is flushed with nitrogen first and THEN vacuumed. I could have them vacuum all of our teas if I wanted, but I don't like them packaged that way.

We seldom order more than 20 of any one tea at a time, but that depends on which tea we're talking about since some types move more quickly than others. We don't want to have any one tea stored here for more than a week if possible. On a slow moving tea, we may only order 3 or 5 of them, just depends. The goal is to keep the stuff moving, and to keep it in our facility for the shortest amount of time - in and out. We're all about fresh. Since we are in Japan, when we are running low on an item all we have to do is call up the grower and order the tea, it will be delivered to us within 24-48 hours of our placing the phone call. We have deliveries coming in nearly every day.

The growers store the tea in special warehouses where the temperature is lowered to near freezing and which is humidity controlled. They pull the tea throughout the year as needed or as we order it.

My experience - I'm not a big "shincha" person, I prefer the tea to be a aged (under proper refrigeration of course) a bit. I think some vendors hype the shincha thing too much. We have customers who only buy from us during shincha season, which is kind of a waste if you ask me because the stuff you buy in October can be just as good. I find a lot of the shincha to be a tad bit on the harsh side. That said, if you know what you are doing, you can compensate by brewing it at a lower temperature for shorter time. Shincha does not mean "better", just my opinion. Gyokuro - it's supposed to be aged. Typically, it's released in the fall. If you're buying first harvest gyokuro in June, the you bought it too early. I'm happy to point that out now so that when you teachat folks see vendor's hyping shincha gyokuro in June, you'll know better.