Talk:Water activity

Food Science vs. Chemistry
Why is this article labelled "food science"? Water activity is a basic chemical property. The default Water_activity page should direct to http://en.wikipedia.org/wiki/Activity_(chemistry) and the food science page should be merged as a subsection of it. zaiken 12:18, 10 October 2012 (UTC) — Preceding unsigned comment added by Zaiken (talk • contribs)


 * Agreed. I tried to change the link to the disambiguation page, but my wiki-editing skills need some work. Does anyone know how to keep this tag at the beginning of the article, but change the page to which it refers? I would like it to link to the more general discussion of activity. JCMPC (talk) 01:43, 16 December 2013 (UTC)


 * Disagree. Water activity is a biological measure used to understand the rate of food going moldy or bad. It is used by the food protection agencies and the concept needs to be described at a level that a household baker could understand. Not the jargony formulas shown and certainly not thermodynamic activity. This page should not redirect.

Useless formula
How useful is this formula to anyone?... ERH = Aw x 100%   ... it is always the same and should just say ERH is the same as Aw except no one uses ERH - certainly not food protection. — Preceding unsigned comment added by 198.103.184.76 (talk) 19:42, 16 July 2018 (UTC)

Definition
The definition of water activity currently posted is not clear enough to help those who don't know (or understand) what water activity is make sense of it. Although not perfect, a better definition that could help readers understand what water activity is might come from The Dictionary of Food Science & Technology, 2nd Ed., Wiley-Blackwell, defines water activity as the "measure of the water vapour generated by the moisture present in a hygroscopic product. Defined as the ratio of the partial pressure of water vapour to the partial pressure of water vapour above pure water at the same temperature. In foods, it represents water not bound to food molecules: the level of unbound water has marked effects on the chemical, microbiological and enzymic stability of foods."

I am not proposing that definition be posted but I think we could start from there and revise it until it makes sense for readers not just in foods but pharmaceuticals, cosmetics, pet food, and other materials. Your thoughts... —Preceding unsigned comment added by Gtvanek (talk • contribs) 21:06, 1 July 2010 (UTC)

Copy Paste
Large sections seem to have been copy and pasted from the reference —Preceding unsigned comment added by Mrbeardy (talk • contribs) 18:06, 12 June 2009 (UTC)

Substance
Is the use of "substance" rigurous? A substance is either a chemical compound or a chemical element. Milk or honey are neither.

Would anybody be opposed to an expanded article? I was thinking adding a table that shows water activity ranges for specific bacteria, and uses of water activity in food quality and shelf stability.

Calculations
Would it be appropriate to list here some of the equations for predicting the Aw of a system? Say, the Norrish equation, Ross equation, etc.

I would love to see some.

"It [water activity] is defined as the vapor pressure of water divided by that of pure water at the same temperature; therefore, pure distilled water has a water activity of exactly one."

should this be: "It [water activity] is defined as the vapor pressure of a substance divided by that of pure water at the same temperature; therefore, pure distilled water has a water activity of exactly one." —Preceding unsigned comment added by 12.46.32.10 (talk) 21:22, 13 March 2008 (UTC)

Copyright problem removed
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Bold textojpopo —Preceding unsigned comment added by 134.225.179.132 (talk) 02:10, 28 February 2010 (UTC)