The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

PH tester

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earthygirl's picture
earthygirl

PH tester

I am looking at Calvels sourdough starter and it states to check ph levels until it has a value of 4.5.  question.   Is this a must have gadget?  any recommendations as to what type to purchase and/or where?

 

TIA  Michele

rideold's picture
rideold

You can buy simple PH test strips at the home brew store.  They come in various ranges of PH.

sphealey's picture
sphealey

I have seen digital pH pens as low as $35 US, although $65 seems to be the lowpoint from laboratory equipment vendors.

I am not sure how well these would work on bread dough though since the mixed dough doesn't have a lot of available moisture. I am starting some inquiries to see if any of my scientific friends can shed any light on this question.

sPh

Update: found this post in the rec.foods.sourdough faq. Not sure what the point of adding the NaOH is, but the technique is to add some (neutral) water to a sample of sour to dissolve it (and presumably let the pH meter work):

===

47. How does one measure the ph of sourdough, and what is the effect
of different ph's?

For sponges and doughs:

*Weigh 15 g of sponge or dough and place it in a polyethylene container.

*Add 100 ml of distilled water to this sample.

*Seal the container and shake until the sponge or dough sample has
completely dispersed.

*Place electrode(s) in the mixture and read the pH value.

*After the pH value has been obtained and recorded, slowly add 0.1N
NaOH from the buret and stir constantly until a constant pH of 6.6
is obtained. Read the buret and record the number of ml of NaOH used
(that is the TTA or Total Titritable Acidity). Take care not to add
the NaOH too rapidly to avoid going beyond pH 6.6.

For bread:

*Weigh 15g of bread, excluding the crust, into a clean dry container.

*Add 100 ml of distilled water, seal the container and shake until
bread disperses into a semi-liquid mixture.

*Determine and record pH and TTA as described for brew.

Some useful information for all you "sourheads" out there:

Overmatured sours, i.e., replenished sours matured over 8 hours at
77F, may build up excessive acidity and the lactic acid bacteria will
start to inhibit the propagation of yeast cells, i.e., slowing the
leavening activity in the sourdough.

A good and fully matured functional sour has a pH of 3.9-4.1 and a
total titratable acidity (TTA) of 13-15 ml. Sours that develop
acidity equal to a TTA of 18-22 ml or higher with a pH of 3.8 or
lower will gradually lose their ability to produce enough carbon
dioxide to leaven bread loaves. Having a high acid content also makes
doughs softer and makes their cell structure break down during
rounding and moulding. This tends to result in an irregular cell
structure with thicker cell walls in the bread crumb and a tougher
bite. This effect is intensified in doughs with a relatively high
water absorption (over 62% of flour weight). However (for all you
artisans out there), bread of this type is acceptable as "signature"
bread served in restaurants or for personal use or for artisan type
bakeries.

Other useful information concerning industry "normal" pH and TTA in
breads and their process:



Sourdough starter 3.9-4.1 pH 14-16 TTA

Mixed dough 4.6-4.8 pH 5-7 TTA

Proofed dough 4.2-4.4 pH 9-13 TTA

Crumb 4.3-4.5 pH 6-7 TTA



*TTA values are expressed as ml of 0.1 N NaOH per 20g sample
(sourdough starter containing 47.6% flour) titrated to pH 6.6

**This is according to the American Institute of Baking, and not the
FDA, so I imagine that would explain some differences in "normal" pH
readings.

-- Dave ===
earthygirl's picture
earthygirl

Thank you soooooo much!