Fridge salami Experiment

[Oddley]

I started this thread because I haven't got a house with many rooms or outhouses to move salami too. I do have a small beer chiller which I can with the right environment mature salami and dry cure bacon.

Unfortunately getting the right environment entails using a bit of science. I'm sorry that not everybody can follow every detail of the discussion but as it is a scientific question then I can't see it being answered without some technical discussion.

I have to do a bit of research to keep up sometimes and am willing to do so to understand the problems therefore the answers. I don't think we should be stopped from discussing these subjects because some people don't understand them.

After all we who are experimenting with this, are putting our knowledge and money into cracking this problem. When we have solved the problems, we will be able to explain how to do it with a good knowledge base. benefiting everybody.

[Oddley]

Markh,
I think the reason that water cools when salt is added, is because of an exothermic reaction. As you lower the freezing point of water, for equalization reasons the water temperature is lowered by the same amount.

At the link below this is explained for grade 4/5/6 (High School) students, so everybody should understand it.

http://www.madsci.org/posts/archives/ma ... .Ch.r.html

[Oddley]

I know I've gone post mad, but just thought of this.

Paul I have thought of an idea for you, that might work for turning the fogger on and off. See link below.

http://www.maplin.co.uk/Module.aspx?Mod ... &doy=23m8D

You can plug the fogger power supply into it, and have it running for say half an hour then turn it off for 15 minutes for example. This should cut out the need for electronics. You will of course have to check it out to see if it can do it the required amount of times in 24 hours, before buying it.

[Paul Kribs]

Oddley

I was thinking along the very same line. I do not have central heating but have slimline electric radiators and they have exactly the same control, and they do work well. You just move the small lugs out on the 24 hour timer to cycle the radiator on and off. At less than a fiver I will have to get one for a trial. Thanks for the link.

Regards, Paul Kribs

[markh]

Paul, the last post I made was in response to Hobbitfeets question:

How does lowering the temperature affect the rate of evaporation, though?

My concern about the Dew Point Temperature is that if your not careful all the water you pump into the air just goes to the cold bit and you might end up with a wet fridge and big 'lecky bills.

Oddley, thanks for the link.

[Hobbitfeet]

Oddley - I think you meant endothermic reaction - easy mistake to make! While I agree that we probably do not need to be too exact to produce an acceptable salami, it may be that some of us are a bit impatient to wait for the cooler months to make salami. Some sort of controlled (and controllable) environment would be of benefit got the warmer or dryer months. (Indeed warmer, dryer climates).

If only we all lived in multiroomed mansions at 2000m!

[Oddley]

Hi Hobbitfeet,

Is not an exothermic reaction where energy is released. If salt is put in water and the water gets colder then there would be a release of energy in the form of heat.

Many chemical reactions release energy in the form of heat, light, or sound. These are exothermic reactions. Exothermic reactions may occur spontaneously and result in higher randomness or entropy (�S > 0) of the system. They are denoted by a negative heat flow (heat is lost to the surroundings) and decrease in enthalpy (�H < 0). In the lab, exothermic reactions produce heat or may even be explosive.

http://chemistry.about.com/cs/generalch ... 51903a.htm

You are right, I suppose many of us would like to make salami year round and don't have the benefit of mountain views.

[Hobbitfeet]

Hi Oddley, I agree, if heat is released, this would result in a rise in temperature - exothermic and a consequent rise in temperature. The fact that energy is taken out of the system to facilitate the reaction between the salt and water means that there is a lowering of temperature - endothermic; the energy released is not released as heat but used at the molecular level in the salt/water reaction. Or so it seems to me -

[Oddley]

Here is a link that is using ice and salt, that explains that it is an exothermic reaction that causes the drop in temperature of the water. Interesting and useful if you like making ice cream.

Yes, it sounds dangerous and the potential for messes seems highly likely, but you'll be surprised at the good, "clean" fun you'll enjoy with your students when you make ice cream. The key to success is to plan smart and follow our simple instructions. The lesson possibilities for this one are nearly endless. Your class can explore the history of ice cream and dairy products, the chemistry of ice, salt and exothermic reactions, or use it an exercise in the scientific method: what if you make the following recipe without salt?

http://www.teachnet.com/lesson/science/ ... 51999.html

[Hobbitfeet]

Here is the link on which I based my comments...

http://www.saltinstitute.org/42g.html

The main passage being...

When ice melts due to the presence of salt, heat is absorbed. This is called an endothermic reaction. The solution of salt (NaCl) in water has a lower vapor pressure than the ice so the ice changes its phase to liquid water. That is how salt reduces the freezing point.

There seem to be a difference of opinions among the "authorities"!

[Oddley]

Oh well if they can't agree it's not worth discussing. I was getting bored with the subject anyway....

[Hobbitfeet]

I quite agree mate. Let's get on with the more important business of sorting out the Controllable Salami Environment Module!

[markh]

The solution of salt (NaCl) in water has a lower vapor pressure than the ice...

Presumably this is why the humidity is lower even when the initial cooling effect is finished and it warms up to ambient again?

[aris]

I had a look at the specs of some of these "beer chillers'. They are incredibly inefficient. Some of them use over 600Kwh per year! Buyer beware - you might be paying alot in electricity bills if you go down this route.

[Oddley]

aris where did you get this info from can you give us an example.

The reason I ask is my beer chiller is 0.8 kwh/ 24 hour. Which by my calculation is 292 kwh/year. which is less than most freezers.