Butter is acidic.
Buttermaking involves converting cream, an emulsion of
butterfat-in-serum, into
butter, an emulsion of serum in butterfat. The cream has about 40%
butterfat and
finished butter has about 80%. Ingredients include water, curd and
salt. Raw
milk pH levels are between 6.5 and 6.8. Measuring the pH detects the
presence of
lactic acid that can lower the pH and affect the flavor. Sometimes
depressed pH
in milk or cream can be corrected by neutralizing with sodium carbonate
and
sodium hydroxide. The raw milk is then separated into cream and skim
milk and
the cream is pasteurized. The cream must cool before churning. A
byproduct of
churning is buttermilk, which is drained before the water and salt are
mixed in.
The butter is then packaged. The final pH value should be near 5 for
maximum
flavor.
Dimitri
As is the brown sugar.

.....IMO the very slight acidity of butter and brown sugar has nothing
to do with the addition of baking soda aside from the baking powder

Besides flour solids had a buffering effect on the batter if the
resulting batter acidity is 'somewhat made negligible" it does not
affect much the acid -base balance of the cookie dough.
However distinctly acidic substance such buttermilk and molasses can
decrease the pH which needs to be neutralized by small amount of baking
soda.hence resulting in a more neutral pH at equilibrium. In the baked
cookie crumb.
Besides such materials can liberate CO2 even during the batter stage
contributing more to the number of gas bubbles in the batter.
Now if you add two leavening agents say baking soda and baking powder
with not a hint of acidulant in the cookie dough, the resulting cookie
will have a slight alkaline crumb pH and as I mentioned previously will
promote a slightly more open grain as well as better crust coloration.
IF the amount of soda added is higher then the pH balance will tip more
to the alkaline side and will promote the formation of soapy aftertaste
and the flavor volatiles that emanate during baking will not as good as
if the soda addition is very minimal.
Therefore as what I related in the earlier post it will not improve
the cookie flavor nor contribute a so called butter flavor to the
product as claimed by the author.
Roy

Vox Humana wrote:
> "Dimitri" > wrote in message
> . ..
> >
> > "Scott" > wrote in message
> > ...
> > >I picked up a copy of Baking 9-1-1 by Sarah Phillips,
> > >
> <http://www.amazon.com/exec/obidos/tg...id=1126808676/
> > > sr=2-1/ref=pd_bbs_b_2_1/002-8697222-1580023?v=glance&s=books>
> > >
> > > and came across a statement that piqued my interest. In her recipe for
> > > sugar cookies, she writes "most cookies use baking powder for leavening;
> > > I chose to use baking soda. It causes the cookies to spread rather than
> > > puff, perfect for a crispy cookie, and have a wonderful buttery flavor
> > > you can't get with baking powder."
> > >
> > > The ingredients a unbleached AP flour, baking soda (1/2 tsp), baking
> > > powder (1/4 tsp), salt, unsalted butter, sugar, an egg, vanilla extract,
> > > and an optional 1/2 tsp lemon extract.
> >
> >
> > Butter is acidic.
>
> As is the brown sugar.