How We Review Products
We read each product's official Amazon listing, keep only what the manufacturer states and calculate a score out of 10 with a public formula: every product starts at 5 and earns points for what its listing declares. Missing data earns nothing. There is no physical testing and no paid placement.
Our method is simple and checkable: we only use what the official listing states, we show our math and we publish the score formula. That way you can disagree with data, not opinions.
Where does the data come from?
From each product’s Amazon.com listing (Amazon.es for the Spanish site): the title, bullet points and technical table. We keep the exact phrase each figure comes from and convert everything to metric, adding US units where they help.
If a listing contradicts itself, we say so on the product page. If a figure is missing, we write that the manufacturer does not publish it. We never fill gaps with general knowledge or other websites.
What math do we do?
The math the listing skips and that helps you decide, always shown step by step:
- Food: kcal per 100 g = kcal ÷ grams × 100.
- Energy: kWh = watts × hours ÷ 1000 (try the drying cost calculator).
- Oxygen absorbers: cc = liters of air × 0.21 × 1000, plus a margin (try the oxygen absorber calculator).
- Emergency supply: daily kcal × people × days (try the emergency food calculator).
How is the DryFoodLab score calculated?
Every product starts at 5 out of 10 and earns points by type. The maximum is 10 and the minimum 0. These are the exact formulas the site uses.
Food dehydrators
- +1 stainless steel trays (+0.5 for BPA-free plastic).
- +1 horizontal airflow.
- +1 reaches 158 °F (70 °C) or more, needed for safe jerky.
- +0.5 timer of 24 hours or more.
- +0.5 capacity: 8 trays or more, or 1 m² (about 10.8 ft²) of drying area.
- +0.5 noise of 45 dB or less.
- +0.5 warranty of 2 years or more.
Freeze dryers
- +1 vacuum pump included.
- +1 cold trap at -50 °C (-58 °F) or colder (+0.5 at -40 °C).
- +0.5 capacity of 4 kg (8.8 lb) or more per batch.
- +0.5 ice capacity of 3 kg or more.
- +0.5 oil-free pump.
- +1 warranty of 2 years or more (+0.5 for 1 year).
- +0.5 tray area of 0.3 m² or more.
- -2 if the listing states implausible figures.
Vacuum sealers
- +1.5 for a chamber sealer (handles liquids); otherwise +1 at 90 kPa or more (+0.5 at 80 kPa).
- +0.5 double seal.
- +0.5 moist mode.
- +0.5 built-in cutter.
- +0.5 roll storage.
- +0.5 accessory port for canisters or jars.
- +1 warranty of 5 years or more (+0.5 for 2 years).
- -1 if the listing has contradictory figures.
Freeze-dried food
- +1 if freeze-dried.
- +1 at 400 kcal per 100 g or more (+0.5 at 350).
- +1 at 25 g of protein per pouch or more (+0.5 at 15 g).
- +0.5 ready in 10 minutes or less.
- +1 stated shelf life of 25 years or more (+0.5 for 5 years).
Emergency ration bars
- +1.5 at 450 kcal per 100 g or more (+1 at 400).
- +1 stated shelf life of 20 years or more (+0.5 for 10).
- +0.5 if eaten without cooking.
Food storage (mylar bags and oxygen absorbers)
- +1 thickness of 7 mil or more (+0.5 at 5 mil).
- +1 kit with both bags and absorbers.
- +0.5 food grade.
- +0.5 zip closure.
- +0.5 labels included.
- +0.5 absorbers of 300 cc or more.
What don’t we do?
We don’t physically test products or publish testimonials. When we explain why a stacked dehydrator dries unevenly or why a bar sealer pulls liquid into the machine, we are describing how the technology works, not our own measurements.
We also don’t accept payment to appear or to move up a ranking. We are funded by Amazon Associates, as explained on our about page.
Which outside sources do we use?
For food safety and emergency supplies we cite official sources: USDA FSIS for jerky, Ready.gov and the European Commission for 72-hour supplies, and oxygen absorber manufacturers’ technical guidance. We link them in each guide, as in 72-hour emergency food.
How often is it updated?
We recheck listings every 60 to 90 days. If a product becomes unavailable or its data changes, we update the page and the review date. If you spot an error, reach us through the contact page.
Frequently asked questions
Why does the score start at 5?
Every product in the catalog already clears a minimum: an available listing with enough data to compare. The score measures how far it stands out above that minimum based on what it declares.
What happens when a listing leaves out a figure?
That criterion adds zero. We would rather penalize missing information than assume a value, so a good machine with a thin listing can score lower than it deserves.
Does the score decide the ranking?
It sets most of the order, but not all of it. Each ranking explains which use every model suits, and a lower-scoring product sometimes wins a specific case, such as the most compact option.
How often do you check listings?
Every 60 to 90 days, and sooner if a reader reports a change. The review date appears on every page.
Why do some freeze dryers get a penalty?
Because some listings state figures that contradict each other or physics, such as capacities that do not fit the machine. We subtract 2 points and explain why on the product page.