What happens to urine when refrigerated?

Refrigerating urine is something that many people may consider doing for various reasons. Some key questions that arise when thinking about refrigerating urine include: what exactly happens to the urine when it is refrigerated, is it safe to do so, and does refrigeration achieve any useful purpose with urine? This article will explore these questions in detail.

Does refrigeration preserve urine?

One of the main reasons someone may choose to refrigerate their urine is in an attempt to preserve it and prevent changes or degradation over time. However, refrigeration actually does little to keep urine preserved or fresh. Here is what happens when urine is refrigerated:

  • The low temperatures slow down but do not stop the growth of bacteria which can break down substances in the urine.
  • Chemical reactions between substances in the urine continue, though at a reduced rate due to the low temperatures.
  • Precipitates form in the urine as certain dissolved minerals come out of solution.
  • The color and odor of the urine change over time as decomposition occurs.

While refrigeration slows the rate of these changes, it does not stop them indefinitely. Urine, even when refrigerated, will still break down and go bad given enough time.

Does refrigeration sterilize or disinfect urine?

Some people may consider refrigerating urine as a way to try and sterilize or disinfect it for various purposes. However, this is not an effective method of sterilization or disinfection. Here’s why:

  • Refrigerators operate at temperatures above freezing, usually from 34-40°F (1-4°C). These temperatures slow but do not halt bacterial growth.
  • Freezing urine temporarily stops bacterial growth, but does not kill all bacteria. Bacteria can revive once thawed.
  • No disinfectant properties arise from chilling or freezing urine alone. To properly disinfect urine requires chemical additives.
  • Some pathogens that could be present in urine, such as certain viruses or bacterial spores, can remain dormant even at freezing temperatures.

Proper sterilization requires heating urine to temperatures high enough to kill all microorganisms present, such as with pressure canning or autoclaving. Refrigeration alone does not suffice.

Does refrigeration alter the urine’s chemical composition?

Refrigerating urine does lead to some subtle chemical changes in its composition over time:

  • The solubility of certain minerals and salts decreases at low temperature, leading to precipitate formation.
  • The rates of certain chemical reactions involving substances normally present in urine will be reduced.
  • Prolonged refrigeration can allow oxidative changes in organic compounds present in urine.
  • Refrigeration may slightly alter the pH of stored urine over time.

However, these types of small chemical shifts do not make a major difference in most situations where someone may consider refrigerating urine. The composition remains largely unaltered.

Can refrigeration concentrate or change the color of urine?

There are a couple ways that refrigerating urine can lead to concentration or color changes:

  • As urine cools, some crystallization of minerals dissolved in the urine occurs. This removes a small volume of water, concentrating the remaining liquid urine.
  • Evaporation is slower but still occurs even in a closed container in the refrigerator. Over time this can concentrate the urine.
  • Color changes from yellow to orange or darker colors occur as breakdown products accumulate through bacterial action and oxidation.

So refrigeration can intensify the urine’s color and concentrate it somewhat, but these are gradual processes taking place over weeks or more. The changes are not rapid or dramatic.

Does refrigeration remove any odors from urine?

Unfortunately refrigerating urine does not help reduce or remove odors. In fact, the odors may intensify over time. Here’s why:

  • The urine odors arise from various volatile compounds. Chilling the urine does not remove these already dissolved compounds.
  • Bacterial action produces various smelly byproducts like ammonia, amines, and sulfides which accumulate.
  • Allowing urine to go septic introduces new additional odors from decomposing organic matter and gas production.

Proper cleanup and deodorizing requires completely removing the source of the odors. Since refrigeration preserves and traps urine, odors persist and build up. The only way to deodorize refrigerated urine is to frequently empty and clean the container before odors get too strong.

What types of containers can be used to refrigerate urine?

To properly refrigerate urine, an appropriate sealed container should be used. Some guidelines on containers for refrigerated urine storage:

  • Glass or plastic bottles with tight sealing lids work well. Avoid metal containers which may corrode.
  • Containers should be washed thoroughly before re-use to avoid contamination.
  • Clear or translucent containers allow observation of any changes taking place.
  • Larger containers minimize the air space above the urine to reduce evaporation and oxidation.
  • Tight seals prevent leaks and prevent the urine odors from spreading. Screw-top lids seal better than snap-top.

Be sure to label any containers used for long term refrigerated urine storage. Sterilized lab sample bottles are a good option as they are made to avoid contamination for samples like urine.

How long can urine safely be refrigerated?

Urine can be refrigerated for up to:

  • 24 hours if collecting a small sample for medical testing purposes.
  • Up to a week if kept in a very clean, sealed container.
  • 2-3 weeks if treated with preservative compounds and stored in an ideal sterile condition.

However, decompositional changes will happen progressively over those time spans. Refrigeration cannot prevent urine from eventually going septic after extended periods.

Does refrigeration produce any hazards with urine?

There are a few hazards to keep in mind when handling and storing refrigerated urine:

  • There is a risk of spillage or leakage if the containers are not properly sealed.
  • Pathogens may be present in fresh urine or gradually accumulate during storage.
  • The urine gives off ammonia and other irritating fumes, especially when old and septic.
  • Long term storage can result in urine deposits building up in the refrigerator.

To avoid issues, use appropriate containers that seal tightly, wear gloves when handling, and avoid long term storage if possible. Thoroughly clean out the refrigerator afterward.

Can urine be refrigerated indefinitely?

No, refrigerating urine indefinitely to preserve it fresh is not feasible. Here is why:

  • Bacterial growth at cool refrigerator temperatures is slowed but not halted.
  • Chemical and oxidative changes to the urine still gradually occur over time.
  • The urine will eventually go septic as proteins and compounds break down.
  • Even in a perfectly closed system, very slow evaporative losses concentrate the urine.
  • The refrigeration system itself will fail over extremely long periods of decades or more.

Practical refrigeration is measured in weeks to months at most before urine becomes badly decomposed. Permanent preservation is not possible simply via refrigeration alone.

Does freezing prevent urine from changing?

Freezing urine stops most decomposition, but still does not prevent all changes indefinitely:

  • Bacteria remain dormant yet alive in frozen urine and can reactivate once thawed.
  • Very slow chemical reactions still take place, especially oxidation.
  • Repeated freeze-thaw cycles accelerate decompositional changes.
  • Water gradually evaporates from even sealed containers reducing the volume over time.

So freezing preserves urine much better than refrigerating, but not perfectly. Urine frozen for years still undergoes gradual changes in quality and composition when thawed.

Could refrigeration concentrate urine enough for survival?

Some survival guides reference refrigerating urine as a way to produce potable water in an emergency situation. However, this is not an effective method for several reasons:

  • The small amount of concentration achieved is not nearly enough to produce safe drinking water.
  • Harmful wastes build up rapidly without water for flushing kidneys.
  • The concentrated urine remains contaminated with bacteria and toxins.
  • Any concentration achieved by freezing takes enormous energy for the phase change.
  • Thawing and distilling enough concentrated urine daily requires impractical amounts of fuel.

Except in cases of immediate life-threatening dehydration, drinking untreated refrigerated urine could do more harm than good. Other condensation and water purification methods work much better in practice.

Does refrigerating provide any medical benefits?

There are no proven medical benefits to refrigerating urine. Claims that it provides benefits for wound therapy, cancer treatment, or other uses are unsubstantiated. Here are some key points:

  • Fresh urine has no unique wound healing properties compared to sterile saline or water.
  • Refrigeration does not remove carcinogens or toxins from urine helpful for cancer therapy.
  • Anyproposed antimicrobial properties of urine are unreliable compared to pharmaceuticals.
  • No health agencies endorse urine therapy uses requiring refrigeration or fresh urine.

While urine may have trace amounts of nutrients, refrigerating it does not produce any significantly concentrated therapeutic compounds. Any minor compounds present degrade with storage.


In summary, refrigerating urine serves little practical purpose. It does not preserve or purify urine, remove odors, or concentrate its composition in any useful way. Changes such as precipitate formation, color shifts, and bacterial accumulation continue despite refrigeration. Any claimed medical benefits of refrigerated urine therapy are false and not scientifically supported. While urine refrigeration may be appropriate for limited medical sample collection, it provides no real benefits for routine or long-term storage.

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