Fridge salami Experiment

[Paul Kribs]

Oddley

I have been to Maplin and bought a mini fogger and spare membrane. On testing it I would concur with you regarding the necessity of having a fan to move the air about. Without it the fog just seems to generate and stay put.

Regards, Paul Kribs

[aris]

Oddley,

Why don't you try the salt & water method mentioned by Len Poli. It would be interesting to see if the humidity levels are like in your mini-fridge with this method:

http://home.pacbell.net/lpoli/htm%20tex ... ontrol.htm

[Oddley]

Paul It's good to know the fogger works. The setup I was considering was to have a pc fan blowing on the cooler element at an angle, with the fogger level on the other side.

I think this will give good thermal coupling and as the air bounces off the cooler element and onto the fogger, will also distribute the moisture evenly.

aris I've had a look, and Len doesn't really say what the salt and water method is. Not that I could find.

[Paul Kribs]

Oddley

I put the fogger in the fridge and put it in a plastic pint glass in the bottom with 2/3 pint of water. The fog did not generate in that depth of water and RH only went from 40 to 49-50. I tipped some water out and so there was about 1/3 pint and the fogger worked. There was nothing in the instructions to indicate this would happen. After 5 mins RH had risen to 80%, now holding at 82%, which I believe is a bit too high. The fridge is almost empty, whether it will make any difference with sausages curing we will have to wait and see.

Regards, Paul Kribs

[Oddley]

Paul that is really useful information. What are the internal dimensions of the fridge you are using?

The RH I believe from what I have read, should be somewhere between 70-80%. Therefore 75% being the figure to aim for. That is where a timer connected to the fogger turning it on and off at regular intervals might work.

I think it probable that when you have wet salami drying this will send the humidity up so probably 82% humidity might be too much.

Perhaps later on for more accuracy a humidity sensor. If I can find one not too expensive and retains a reasonable accuracy.

[Paul Kribs]

Oddley

The fridge dimesions are 29"H x 20"D x 21"W. Since my last post I have been monitoring and it is cycling between 75%RH and 83%RH, but the temp is set on 4.9oC. Don't want to knock the temp up yet as it will defrost the fridge.. it's a bit fickle. It's pleasing to know the fogger delivers, just a case of control.

is this the kind of thing you are looking for?
http://www.anglia.com/newsarchive/566.asp?article_id=1350

BTW, it took approx 5 hours for the 1/3 pint to evaperate below the level of the switch. Bear in mind that was a narrow glass so performance would be better using a large shallow container such as a 2" deep butchers acrylic tray.

Regards, Paul Kribs

[markh]

Oddley

Did you try just the fan on your original fridge setup? If so, did it have any effect on the frost/ humidity?

Paul, are you seeing a frost buildup on the cooling elements in yours?

[Oddley]

markh, I have not yet tried the fan idea. I was not going to go to maplin till next month but as there is such interest I will try to get there before. No promises though as I have family commitments.

Paul thank you for the link but with all these things electronic it is not finding the component, it is finding it retail.

[Paul Kribs]

markh

After only 5 hours there was no noticable build up of frost on the cooling plate. Most of the evaporated fog had condensed and was lying in the salad tray. I did notice it was cutting in more so maybe if I had left it for a few days there may have been a noticable build up.

Oddley & markh

These foggers are 24 volt DC/800mA, power consumption 19.2W. Having monitored it for 5 hours it averaged 80%-83%RH. Would it be viable to bridge a drop diode across the 24v wires? and would it bring it down to the mid 70's range? I believe these diodes drop it by 1.2v. Would the fogger still work, but to a lesser degree?
I am pretty new to all this so if I am way off the mark be gentle with me..

Regards, Paul Kribs

[aris]

aris I've had a look, and Len doesn't really say what the salt and water method is. Not that I could find.

I would think it is just a pound of salt in a pan, and just covered with water - not floating, just enough to keep the salt wet. Give it a try.

[Hobbitfeet]

I have used the salt method to keep the humidity in a cigar humidor made from a tupperware box at around 70% - it works, so should work for our salami purposes. How does lowering the temperature affect the rate of evaporation, though?

[markh]

I'll have a crack at it - at least my understanding of it - apologies if either too simple or too technical!

Water, like pretty much everything else (including metals) has a 'vapour pressure' (in the case of water its related to the absolute humidity) where molecules are knocked off the surface (evaporating). If hot, the molecules are banging about and more get knocked off and the humidity rises - taking away some of the heat and cooling it. This is true even when its ice.

At some point the rate at which they boil off is equal to the rate at which they recondense and the air is saturated at that temperature - an equilibrium. If the temperature rises to the point where the vapour pressure is the same as the air pressure, it boils. This is why at altitude, with a low pressure, water boils at a lower temperature.

Conversely, because low temperature air cannot support as much vapour as warm air, if there is a cold surface more molecules condense than boil off and so you get those drips of water on the perfectly chilled glass of amber nectar you're about to savour... sorry, off the subject a bit

That's the Dew Point - any surface colder starts to get condensation - or if cold enough, frost. It also starts to warm - its gaining additional energy - and the amount of water in the air goes down - the overall humidity drops.

The Relative Humidity is the current vapour pressure compared to the maximum at the current temperature as a percentage.

The bottom line is that in a sealed box, surfaces below the dew point mean lower relative humidity. If you use 'forced' humidifying techniques the excess moisture will tend to condense on to them, which also warms them - Paul, that is probably why you are seeing it cutting in more often, and why I was asking if Oddley had tried the fan approach - hopefully raising the element above the Dew Point for the overall temperature.

I have done some Dew Point calcs (in Excel) for the area of interest they are:
Relative Humidity
Temp 60% 65% 70% 75% 80%

8 0.7 1.8 2.9 3.8 4.8
9 1.7 2.8 3.8 4.8 5.7
10 2.6 3.7 4.8 5.8 6.7
11 3.5 4.7 5.7 6.7 7.7
12 4.5 5.6 6.7 7.7 8.7
13 5.4 6.6 7.7 8.7 9.6
14 6.4 7.5 8.6 9.6 10.6

Afraid it doesn't seem to format properly - email me if anyone wants a copy of the spreadsheet.

Now, if someone could just explain why the water with salt in would be colder than the water on its own...

[Paul Kribs]

markh

I'm afraid you compeletly lost me. Excuse my lack of itnillect. I unerstand and dribble about the bit pertaining of the beer. I find this all a bit complicated trying to ascertain the correct conditions for temp/humidity for curing. Not wishing to sound rude I am trying to come by way of a method for curing chorizo, salami etc with the least amount of hassle. They appear to do it OK in the italian mountains and in france and I am aware that their conditions are right, but also realise it is conjstantly monitored and adjusted accordingly.. that is what I would like to attain here, hence the experimentation.

regards, Paul Kribs

[Franco]

Whilst the conditions at the start of the salami making process are very important ie high temperature and high humidity(to allow the starter culture to work) I personally have had good results even with random conditions.

I have started curing in one room and because of lack of space I have moved the salami to another room with different conditions with no adverse effects.

Once you have made salami a few times you know when the conditions aren't right and if you feel the outside of the salami is drying too quickly it can be moved to a different part of the house.

Good results can be achieved with experimentation, don't think that it needs to be too technical, as Paul rightly states people have been curing salami for hundreds of years in without fridges, chillers, humidity chambers etc.

For first time salami makers I would recommend a small bore salami, these mature quickly and are almost foolproof.

Franco

[Paul Kribs]

Franco

That is reassuring to know, it is a very apprehensive project because of the effects of the cure.

Regards, Paul Kribs