Not sure if this study has been post before, but I haven't seen it and this is the most relevant recent post about tea, so here we go. I've never heard of cold steeping tea before but this claims that it's better for white teas.
http://www.sciencedi...a7015af73895d64
Abstract: A new popular way of making tea, especially in Taiwan, is to steep leaves in cold water. Here we investigate whether antioxidant activity of teas may be affected by hot or cold water steeping and if this correlates with their polyphenol content and metal-chelating activity. A set of five loose tea samples, consisting of unblended and blended teas, was analysed following their infusion in either hot water (90 °C, 7 min) or cold water (room temperature, 2 h). Antioxidant activity, measured as hydrogen-donating ability, using the ABTS· and DMPD assays, showed no significant differences among hot or cold teas, except in the case of white tea, where significantly higher values were obtained after cold water steeping, a recurrent finding in this study. The antioxidant activity of the teas correlates well with their total phenolic content and metal-chelating activity. Cold teas were, however, generally better inhibitors of in vitro LDL conjugated diene formation and of loss in tryptophan fluorescence. The results of this study contribute to gaining further knowledge on how the potential health benefits of this popular beverage may be maximised by the different methods of preparation.
I read the study and to summarize it I'd say cold steeped white tea is the way to go.
A few quotes:
In the present study, in general, steeping teas in cold water or hot water does not significantly affect the TPC content. However, for white tea, surprisingly, TPC is higher when it is steeped in cold water instead of hot water. This finding suggests that certain phenolic components, unique to white tea, but not to others, might be broken down or transformed at high temperatures, contributing to the lower content observed.
For the antioxidant activity, measured as hydrogen-donating ability, using the ABTS or DMPD assays, the results here reported suggest that, in general, there are no significant differences in this activity among hot or cold teas, except in the case of white tea, where significantly higher values are obtained after cold water steeping, possibly due to the reason suggested above.
Also using cold water should make it taste better since they also refer to another study in which this was the conclusion:
catechins, caffeine and gallic acid were released from bag teas as hotter water was used and that these increased with increasing duration
How they prepared the teas, which seems highly relevant:
A set of five loose tea samples was analysed, which included four unblended teas: black tea (chinese Lapsang Souchong), white tea (chinese Pai Mu Tan), green tea (China Special Gunpowder), oolong tea (from Fujian Province – China), and one blended black tea (Lyons Gold Brand which is a blend of African and Indian black teas) denominated Lyons in the figures. All were purchased from local retail shops. Prior to tea preparation, the teas were ground using a pestle and mortar to obtain a homogeneous fine powder for each kind of tea. Cold tea infusions were prepared by placing 0.5 g of tea in 50 ml of mineral water at room temperature and gently agitating for 2 h under magnetic stirring. Hot tea infusions were prepared by placing 0.5 g of tea in 50 ml of mineral water at 90 °C and gently agitating under magnetic stirring for 7 min. Both hot and cold infusions were then filtered through Whatman paper filters (43–38 μm) and diluted appropriately with water according to each specific assay. Throughout the paper, the terms hot tea and cold tea will now be used to express the two types of infusions.
Well that seems like a great method if you have a magnetic stirrer and don't mind using a filter afterwards. For someone as lazy as me it seems like a hassle though.
I therefore propose the follow method to prepare tea: get good quality white tea in bulk along with sealable tea bags.
1. Grind up the white tea with a mortar and place it in the sealable tea bag. Preferably just before use.
2. Add the tea bag to a huge pitcher of water and leave it in for at least two hours or just indefinitely to get the most out of the tea. This might increase catechins, caffeine and gallic acid as mentioned above but should also give you more of the good stuff. Stirring often is probably a good idea too.
Anything lower than room temperature weren't tried by the study but for those of us feeling experimental putting the pitcher in the fridge would make some great cold steeped white ice tea when berries are added to taste. Personally I'll probably I'd probably just leave the pitcher in room temperature and add some frozen berries to each cup of tea to cool it down and give it some taste.
Ground up white tea in a pitcher of water and filtering the infusion for each new cup you take might also be a an option if you prefer filters rather than sealable tea bags. If so,
magnetic stirrer anyone? :p
Edited by aLurker, 10 August 2010 - 03:02 AM.