Why we are increasing our STR cask production


STR casks are used red wine barrels that are rejuvenated so that they can be used again by distilleries to make some interesting flavours and make some considerable savings. Here at Luso Barrel we have been investing quite heavily in new machinery to enable us to increase our production of STR casks to meet growing demand, and here we will explain a little more about the STR process and why it is important.

STR stands for Shaving, Toasting, Rechar and the process runs like this:

  • We take used red wine barrels and remove the heads to expose the inside staves of the barrels
  • Using our special shaving robot, we remove the exposed surface layer of the staves (taking away the most wine saturated layer of oak ro leave behind semi-virgin oak, but that still carries some flavours from the wine
  • Using are traditional toasting and charring methods (using only flames from our wood off-cuts) we toast and rechar the shaved barrels to customer specification
STR cask
Here you can see the staves of a used red wine barrel after it has been shaved – notice that you can seill see some signs of red wine staining and that the smooth inside surface of the staves is maintained

The shaving will of course remove many of the red wine flavours, but the idea is to leave behind just a hint of these flavours, but by toasting and recharring the tannins and other more powerful chemical compounds in the wood are broken down into more desirable sugars and other more subtle flavours. So with the STR cask you will get this unique blend of new and used oak barrels flavours. Furthermore you get a major cost saving , with our STR casks costing much less than our virgin oak casks.

Whilst we can use conventional methods to toast and rehcar our STR casks, the shaving part is much more complex. This is because to effectively shave the barrels, it has to be done along the grain of the staves: it would be much easier to shave the barrels going round and round the inside of the barrels, but this leaves to plucking from the wood surface and a very uneven finish. Our solution is a robot arm that goes in and out of the barrel along the length of the stave, programmed to follow the bilge profile of the barrel, shaving the staves one by one. The only alternative to this is to shave the staves in the more traditional way (which we have always done before), which is to disassamble the barrel and shave the staves one by one before reassmbling it.

The only complexity for the toasting of STR barrels is that both heads of the barrel have to be removed in order to give a correct toast to the barrel – firing the barrel from one end with the other end still sealed will trap all the smoke inside the barrel, which can easily lead to an overwhelming smokiness to the wood, which can really impact on flavour further down the line – removing both heads gives a lot more work for the cooper as it is not a simple process given that the hoops have to be loosened and retightened. It really is incorrect to cut corners like this however, because the flavour profile of STR casks is just as important to preserve as that of virgin or other used barrels.

Whilst the cost savings on STR casks compared to virgin oak is of course a major attraction, you should not think of STR casks as just a second rate alternative. Many distilleries actively require STR casks for some of their brands because they like the unique flavours that they produce. With an STR cask you get a halfway house between virgin oak and used oak, so whilst you will lose some of the stringency that fresh oak can give, you will still have a hint of the fruity flavours that come from the red wine, which will still have some representation even with the heavily impregnated top surface layer removed. So STR casks can be a subtle alternative to used barrels or fresh barrels as they are somewhere in the middle when it comes to flavour profile.

Like so many things in the cooperage trade, we keep confidential some of the secrets of our STR process, but we would like to think that the quality of our STR casks speaks for itself! If you are interested in sourcing STR casks or need some further information, please do not hesitate to get in touch.

Scroll to Top