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I want to make a dried cheese powder to use as seasoning and, if possible, extend shelf life and reduce weight.

I don't have a freeze dryer so I'll need to use air for that. Problem with using dehydrators for cheese is that above certain temperatures protein matrix gets destroyed, fat escapes, and you end up with a sub-par, separated product. It's still edible and it still has somewhat extended shelf life, but it's oily mess not pleasant to use and needs to be refrigerated, freezed and preferably vacuum sealed.

I can use my oven in dehydrator mode, and I can set any air temperature between room temperature and baking one. I usually dry meats, fruit and vegetables at around 40°C / 104°F. For fastest drying, I of course want as high as I can get, but what's the temperature I need to be below to keep cheese from separating?

If cheese kind matter, assume inexpensive European Gouda. Specifically this one* if it matters, but I hope for answers to be as universal as possible.

* I'm not affiliated with this brand, it simply was cheap enough to experiment on, but tasty enough to make it worthwhile, in my purely subjective opinion. So that's what I got.

Mołot
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    A lot of the resources I checked say that you cannot dehydrate cheese in a dehydrator, you need to freeze-dry it: https://www.thepurposefulpantry.com/do-not-dehydrate-list/ – FuzzyChef Sep 28 '22 at 01:15
  • @FuzzyChef sure you can, if you don't mind losing fat. I kinda do mind, but it's not worth couple thousands of dollars to me. Currently trying at 40°C, I'll post an answer to tell everyone if it works in like 24 hours. Maybe it'll separate, if so I'll have worse, but still usable powder. Of course, I'll need to re-grind it then. – Mołot Sep 28 '22 at 01:51
  • @FuzzyChef I edited the question to acknowledge issues with dehydrated cheese that separated. – Mołot Sep 28 '22 at 01:58
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    What's your goal with drying the cheese? Just extend the shelf life? Besides flavor, what else do you want to preserve? I might have a different solution. – Luciano Sep 28 '22 at 08:20
  • @Luciano ideally, to get dust for dusting dishes. But removing weight and extending shelf life would be great. – Mołot Sep 28 '22 at 10:24
  • Molot: yeah, I'm not posting what I have as an answer because I've never tried it. Just noting some obstacles you might face. – FuzzyChef Sep 28 '22 at 19:10

2 Answers2

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I believe a great temperature to dry cheese is around 4°C.

No, that's not a typo. I have observed cheeses wrapped in parchment paper drying in my fridge while keeping (most) of the fat and the flavor. It will take longer than using a hot dehidrator, but it will not break the protein down as it would at high temperature.

I currently have some leftover cheese that dried in my fridge, I just got lazy to grind it but it's there for months without signs of spoilage.

Luciano
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  • Any thoughts as to how? From the way I've seen accidentally exposed edges dry out I'd guess: slice thinly, spread out open in a single layer, chop/grind after a few days. I froze some cheddar recently (they only had huge blocks in the shop that day) in a slightly oversize container, and noticed a lot of ice crystals and some slight drying when I defrosted a chunk – Chris H Sep 28 '22 at 12:44
  • Ideally you'd probably warm the cheese slightly (still below 20°C) while it's in the fridge (hard cheeses such as cheddar can be stored at room temperature - [USDA](https://ask.usda.gov/s/article/Does-all-cheese-need-to-be-refrigerated)) – Chris H Sep 28 '22 at 12:46
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    @ChrisH Grate it and spread it out on a plate? – dbmag9 Sep 28 '22 at 12:51
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    @dbmag9 possibly, grating tends to give clumps. Slices would sit on a ventilated tray like a dehydrator tray, though grated could sit on such a tray on cheesecloth – Chris H Sep 28 '22 at 12:54
  • @ChrisH whenever I leave cheese for long enough the whole piece dries out. I guess grating would help dry the fastest, provided there's some way to keep external moisture out of it - slices would probably be a good compromise. – Luciano Sep 29 '22 at 10:03
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    @Luciano IME it would be likely to go mouldy in the clumps while the outside would dry. Grating seems to encourage mould formation, probably because of all the handling – Chris H Sep 29 '22 at 11:17
  • I would argue that even 4°C is too warm to deserve the term "optimal". Even if we don't nitpick about the low efficiency, it is not even effective. I also have had cheese go dry on me in the fridge, but I also have had it go moldy - and mold can be dangerous long before it is visible or smellable. Fridges tend to lack the ventilation needed for proper ventilation. So it will not only fail sometimes, it will fail undetectably, which is the most dangerous way of failure. – rumtscho Sep 29 '22 at 21:39
  • @rumtscho Drying isn't usually the goal when I put cheese on my fridge... I'm not claiming it's an optimal method, this is just my observation. More of a starting point for what's described in borkymcfood's more complete answer. – Luciano Sep 30 '22 at 14:27
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Short answer: slow-dry the cheese under refrigeration.

Long answer:
The cheese protein matrix (casein micelles) relies on a fine balance and arrangement of milk fats finely dispersed in small globules within the protein to maintain its structure [1,2]. Heating the cheese has multiple effects - the fats flow more easily, allowing the fat globules to coalesce and break the balanced arrangement. The micelles themselves also lose their structure when heated [3,4], though some may remain intact up to 70C[1].

The milk fats, however, have a wide range of melting temperatures from -40C to 37C [5,6]. Some will remain liquid under refrigeration and most will be solid up to and above room temperature.

Milk fatty acid melting points

Fatty acid composition and melting points in fluid raw milk.
From Fee & Chand, Table 3 [6].

The table above highlights the major fats fatty acids in liquid milk, and will vary in cheeses.
The freeze-drying suggested by FuzzyChef relies on sublimation to remove water at or near room temperature; a more home-chef friendly option would be to simply use relative humidity gradients (drier air) to dehydrate the cheese, though much more slowly. This post and answer (work-in-progress) What is the science of drying/dehydrating meat? Biltong, jerky, etc explains the basic concepts for dehydration.

For your equipment, you can use room-temperature air at a high flow rate to dehydrate your cheese, though for food safety it's preferable to perform this under refrigeration - it's much slower, but you can increase surface area for drying by thinly slicing or coarsely grating the cheese, then grinding to your desired final particle size. More fatty acids milk fats will solidify as well, helping the casein retain its structure better during water loss.

You could also lightly dust the cheese with a neutral easily soluble starch, i.e. corn or rice, to sequester some of the fats that will be released.

Basic biology clarification regarding the table of fatty acids above:

'Milk fats' are triglycerides composed of three fatty acids attached to a glycerol chain. The melting points of the component fatty acids affect the melting point of the triglyceride as a whole, and will occur between the highest and lowest fatty acid melting points. The melting point of each fatty acid does not in itself present an 'upper limit'.

Triglycerides in milk tend to present with three different fatty acids unless one component presents at higher than 33% of the total, due to environmental or animal variation factors.

The following excerpts from Principles of Dairy Chemistry [Robert Jenness and Stuart Patton, 1959, New York, John Wiley and Sons, 1959, p38, 45-47] provide a more technical explanation and reference a complete milk fat melting point of 41C:

p38

p45a

p45b

p46

p47

[1] The cheese matrix: Understanding the impact of cheese structure on aspects of cardiovascular health – A food science and a human nutrition perspective.
Emma L Feeney, Prabin Lamichhane, Jeremiah J Sheehan.
https://doi.org/10.1111/1471-0307.12755

[1] On the Stability of Casein Micelles.
Pieter Walstra.
https://doi.org/10.3168/jds.S0022-0302(90)78875-3

[3] Lipids in cheese.
Michael H Tunick.
http://dx.doi.org/10.1002/lite.201500015

[4] Effects of Homogenitation and Proteolysis on Free Oil in Mozzarella Cheese.
Michael H. Tunick.
https://doi.org/10.3168/jds.S0022-0302(94)77190-3

[5] Physical Properties of Milk Fat.
J.M. deMan.
https://doi.org/10.3168/jds.S0022-0302(64)88880-9

[6] Capture of lactoferrin and lactoperoxidase from raw whole milk by cation exchange chromatography.
C. Fee, A. Chand.
https://doi.org/10.1016/J.SEPPUR.2005.07.011

borkymcfood
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    That table is interesting, but in my experience cheddar releases quite a bit of oil between room temperature (familiar from cheeseboards and packed lunches, where it softens a bit but no more than that) and about 30°C (bike camping in surprisingly sunny conditions) - that sets a rough upper limit, but the mechanism behind what I found doesn't obviously derive from the fat composition – Chris H Sep 29 '22 at 06:21
  • It would be easy to rig a fan inside a fridge, blowing over the cheese - either 5V and a USB battery pack or a 12V computer fan and run wires in through the door seal. Some very gentle heat could be added - perhaps an old-fashioned torch (flashlighht) bulb of about the right voltage, for about 1W, before the fan with something to ensure the fan pulls air over the heater. – Chris H Sep 29 '22 at 09:08
  • @ChrisH the table is for the major fatty acid components in milk triglycerides, to give an idea of the range of melting points. As stated above this will vary from cheeses - lipase activity from bacterial/fungal culturing will shorten the fatty acid chains and reduce their melting point, giving even more variation by type of cheese. The fatty acid composition of individual triglycerides will affect melting point, between the lowest and highest melting acid. – borkymcfood Sep 29 '22 at 09:37
  • @ChrisH The softening and release of liquid fats by your cheddar between room temp and 30C is in line with the referenced literature. It's still not the 'upper limit' of liquid fat release if the cheese retained its structure while softening - some triglycerides are still in solid state. The 'upper limit' occurs with complete melting and loss of casein micelle cohesion, with the very obviously melted blob of protein in a pool of liquid fat, above 37C. – borkymcfood Sep 29 '22 at 09:45
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    @ChrisH the suggestion for a small fan for air movement in the fridge is good, the suggestion for a heat source is completely counterproductive to the reason for refrigeration. – borkymcfood Sep 29 '22 at 09:48
  • Very gentle heat would increase drying, without warming the cheese appreciably. Note that I suggested a *very* low power. It was a bit too low - now I've run the numbers that 1W with a PC fan would only warm the air forced by the fan by about 0.2°C. I was aiming for more like 1°C - so still fridge cold, but with a lower RH because of the slightly higher temperature, taking your RH gradient and enhancing it. To be counterproductive you'd have to put in 10s of W, which would make the fridge work a lot harder and would make me worry about the other food. – Chris H Sep 29 '22 at 12:06
  • It might be a good idea to run the numbers yourself before saying that fridge cold, but slightly less so, is counterproductive – Chris H Sep 29 '22 at 12:07
  • @ChrisH quick napkin math - CV of 0.2 Wh/(Kg*C) with approx. 0.38 kg air in a ~300 L fridge gives me ∆T +0.5C for 0.2 W and +2.6C for your 1 W bulb, please check that. – borkymcfood Sep 29 '22 at 16:28
  • @ChrisH given the ∆T and 1) household fridges barely maintain 0C-4C due to improper consumer practices, based on professional experience, 2) nitpicking about Listeria - https://doi.org/10.1111/j.1365-2672.1988.tb01898.x , adding a heat source to the inside of your fridge is very counterproductive for food safety - and for our friends in Europe, not helpful with the energy crisis. – borkymcfood Sep 29 '22 at 16:35
  • The fridge runs (intermittently of course, as it has a couple of orders of magnitude more cooling power than the heat load ) and cools the air again, so I war considering the amount of air pushed around by a fan, not the static air in the fridge. That would be an appropriate amount if you turned it off. As for the energy use, you could make up for what's used in a day by what I suggest by turning off a 2kW cooker 43 seconds sooner. It's negligible which is why the fridge can handle it. Anyway, this is getting a bit silly now, so I'll leave it there – Chris H Sep 29 '22 at 19:39