pH levels in pear juice for Perry

[Ron Miller]

I have 300 litres of Packham pear juice to make perry. The brix is 11
degrees and the pH 4.75. Is this an acceptable pH level for perry or
should I add some acid? If so would I add malic acid? Also what is a
safe level of potassium metabisulphite...I'm looking at 150ppm.

Regards

Ron

[Andrew Lea]

pH 4.75 is far too high for any cider or perry. Received wisdom is that
you should bring it down to pH 3.8; certainly below 4. You could use
malic or citric - pars contain both. There was a thread here recently
about the growth of Clostridium sp in high pH pear juice. Certainly
unpleasant, potentially even toxic.

The SO2/ pH tables are widely available. There is a chart and discussion
for cider here http://www.cider.org.uk/sulphite.html For perry it is
recommended to add a flat 50 ppm extra because pear juice contains
significant free acetaldehyde which is a major sulphite binder. In most
jurisdictions a total of 200 ppm must not be exceeded; hence one reason
to drop the pH.

Andrew

--
Wittenham Hill Cider Pages
www.cider.org.uk

[Ron Miller]

Thanks Andrew, very helpful advice.

Ron

On Aug 6, 4:31 am, Andrew Lea <y...@cider.org.uk> wrote:
> On 06/08/2011 09:05, Ron Miller wrote:
>
> > I have 300 litres of Packham pear juice to make perry.  The brix is 11
> > degrees and the pH 4.75.  Is this an acceptable pH level for perry or
> > should I add some acid?  If so would I add malic acid?  Also what is a
> > safe level of potassium metabisulphite...I'm looking at 150ppm.
>
> pH 4.75 is far too high for any cider or perry. Received wisdom is that
> you should bring it down to pH 3.8; certainly below 4. You could use
> malic or citric - pars contain both. There was a thread here recently
> about the growth of Clostridium sp in high pH pear juice. Certainly
> unpleasant, potentially even toxic.
>
> The SO2/ pH tables are widely available. There is a chart and discussion

> for cider herehttp://www.cider.org.uk/sulphite.html For perry it is