On the heels of my overly bretty experiences with Pesquera wines comes
this latest article from Decanter.

JJ

Brett may be caused by new oak
November 21, 2007

New oak barrels may be responsible for brettanomyces, consultant
winemaker Matt Thomson has said.

Thomson, who consults for New Zealand's Saint Clair and Kim Crawford
wineries as well as Italian and French producers, was speaking about
the yeast infection that can strip a wine of its fruit and create
aromas described as 'mousey' or 'horsey', at a seminar on
brettanomyces hosted by Liberty Wines.

He said, 'Although some scientists don't agree, many winemakers *
myselfincluded * believe that the source of brettanomyces lies in new
barrels coming into a winery.'

Once a winery is infected by the rogue yeast, it can be extremely
difficult to get rid of as the risk of cross-contamination is high and
preventative measures can limit the range of vinification techniques
used by winemakers.

Thomson believes that the incidence of brettanomyces has increased in
recent years. 'I think it's a relatively new thing in many Old and New
World regions,' he said, adding that he thinks the increase is,
'partly down to new wine styles that are low in acidity and relatively
high in residual sugar, but also due to increased demand for new oak
barrels.'

He speculated that this increased demand for new oak may have led to
the harvesting of wood from infected sources * and that the toasting
process involved in creating new barrels may produce compounds that
may be a source of food for the Brettanomyces cells.

wrote:

> On the heels of my overly bretty experiences
> with Pesquera wines comes this latest article
> from Decanter.
>
> JJ
>
> Brett may be caused by new oak
> November 21, 2007
>
> New oak barrels may be responsible for
> brettanomyces, consultant winemaker Matt Thomson
> has said.
>
> Thomson, who consults for New Zealand's Saint
> Clair and Kim Crawford wineries as well as
> Italian and French producers, was speaking about
> the yeast infection that can strip a wine of its
> fruit and create aromas described as 'mousey' or
> 'horsey', at a seminar on brettanomyces hosted
> by Liberty Wines.
>
> He said, 'Although some scientists don't agree,
> many winemakers * myselfincluded * believe that
> the source of brettanomyces lies in new barrels
> coming into a winery.'
>
> Once a winery is infected by the rogue yeast, it
> can be extremely difficult to get rid of as the
> risk of cross-contamination is high and
> preventative measures can limit the range of
> vinification techniques used by winemakers.
>
> Thomson believes that the incidence of
> brettanomyces has increased in recent years. 'I
> think it's a relatively new thing in many Old
> and New World regions,' he said, adding that he
> thinks the increase is, 'partly down to new wine
> styles that are low in acidity and relatively
> high in residual sugar, but also due to
> increased demand for new oak barrels.'
>
> He speculated that this increased demand for new
> oak may have led to the harvesting of wood from
> infected sources * and that the toasting process
> involved in creating new barrels may produce
> compounds that may be a source of food for the
> Brettanomyces cells.

As a wine maker, I would say it is possible but
the most likely cause(s), in my opinion, is high
pH, low acid wines, lack of proper levels of free
SO2, barrels not topped up, and extended time on
the lees. Probably most wineries and grapes at
harvest are going to have Brett present. The
goal is to keep it in check and prevent it from
growing. I would think there is a more
likelihood of Brett in old barrels.