Do you splodge or spread your brown sauce?

Do you splodge or spread your brown sauce?


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How does refrigeration affect ph levels Mr. Esk?


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pH can indeed vary with temperature. The reasons why depend on the context, but even a simple solution of a weak acid (HA) will exhibit a (weak) temperature dependence. The pH is given by the Henderson-Hasselbalch equation:

pH = pKa + log { [A-]/[HA] }

where Ka is the equilibrium constant for the reaction

HA ---> H+ + A-

( ka = [H+][A-] / [HA] )

and pKa = - log Ka .

Ka is itself a function of temperature, since it is related to the Gibbs free energy of reaction (delta G) by the equation

delta G = - RT ln Ka = -2.303 RT log Ka = 2.303 RT * pKa

so we have

pkA = delta G / (2.303 RT)

delta G is itself given by

delta G = delta H - T * delta S

where delta H is the enthalpy of reaction and delta S is the entropy of reaction. Combining these, we get

pKa = (delta H / (2.303 RT)) - (delta S / (2.303 R))

If we assume for the sake of simplicity that delta H and delta S are approximately independent of temperature T (constant), then the variation with temperature is determined by the sign of delta H. For example, if delta H is positive (endothermic dissociation), pKa gets smaller as the temperature gets larger. A decrease in pKa amounts to an increase in Ka, which means that the reaction favors dissociation more as temperature increases (in agreement with LeChatelier's principle). This increases [H+] and decreases the pH. If the reaction is exothermic the opposite effect will be observed.

My point was that if sauce is kept in the fridge to reduce contamination then it is a pointless exercise as most micro-organisms cannot grow in an environment with the same pH as tomato ketchup.
 

My point was that if sauce is kept in the fridge to reduce contamination then it is a pointless exercise as most micro-organisms cannot grow in an environment with the same pH as tomato ketchup.

Brown sauce lad, we were talking about brown sauce. Can you please alter your forumla accordingly, showing all working-out as you go?

And people put stuff in the fridge to keep it cold. If I want something de-contaminated I'll take it to a hospital. And I think we all agree that anyone who took contaminated tomato ketchup to a hospital for de-contamination, in the hope that de-contamination would somehow correct the faux-pas of using ketchup instead of brown sauce in a bacon butty, would probably be somewhat disappointed with the result.

Glad to have been of help.









Fair play with the chemistry/biology lecture though.
 
Brown sauce lad, we were talking about brown sauce. Can you please alter your forumla accordingly, showing all working-out as you go?

Glad to have been of help.

.

Due to the significant mount of tamarind in HP sauce at a very low pH of 1.8 there is even less requirement to place the sauce in the fridge.

However your answer begs the question why add cold sauce to hot bacon?
 

Due to the significant mount of tamarind in HP sauce at a very low pH of 1.8 there is even less requirement to place the sauce in the fridge.

However your answer begs the question why add cold sauce to hot bacon?

I think you missed the white text.

But I also refer you to my earlier response; the sauce, be it brown or red, is added to the bread rather than the bacon. At least it is in my house.

The universe demands that sauce be placed in the fridge - why else would there be suitably-sized racks in the door?
 
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