What is the safe internal temperature for chicken?

The USDA recommends a safe minimum internal temperature of 74 °C (165 °F) for all poultry — whole birds, ground poultry and leftovers. This temperature must be reached at the thickest part, not near bone. Source: USDA FSIS Chicken Guide.

What is the food danger zone?

The danger zone is 4–60 °C (40–140 °F) — the range where bacteria multiply most rapidly. The UK Food Standards Agency and the USDA both advise keeping perishable food in this range for no more than 2 hours total (1 hour above 32 °C).

At what temperature do different cooking fats smoke?

Smoke points vary by fat and how refined it is. Butter smokes around 150 °C, extra-virgin olive oil around 190 °C, canola around 205 °C, and refined avocado oil up to 270 °C. Values are approximate — see the Serious Eats smoke point explainer for why they vary.

What is bread hydration and why does it matter?

Hydration in bread is the ratio of water to flour, expressed as a percentage using baker's percentages. A 65% hydration dough has 650 g of water per 1 kg of flour. Higher hydration creates a more open crumb but requires more skill to handle. Sandwich bread sits at 60–65%; ciabatta at 75–85%.

Why does water boil at a lower temperature at altitude?

At higher altitudes, atmospheric pressure is lower. Water boils when its vapour pressure equals the surrounding pressure, so it boils at a lower temperature. At 3 000 m, water boils at approximately 90 °C instead of 100 °C. This means food takes longer to cook. The Engineering Toolbox boiling-point table has precise values by altitude.

Kitchen data

The numbers behind good cooking.

Temperatures, ranges and weights as clear charts. Every figure shows where it comes from, and approximate values say so.

Browse the data How we source it

74 °C Poultry, cooked through 165 °F · USDA

4 °C Fridge, at or below 40 °F · USDA

-18 °C Freezer 0 °F · USDA

2 hours Longest at room temperature 1 hour above 32 °C · USDA

Safe minimum internal temperatures

Measured with a probe at the thickest part. Source: USDA.

Poultry, whole or ground 74 °C · 165 °F

Ground beef, pork, lamb 71 °C · 160 °F

Egg dishes 71 °C · 160 °F

Beef, pork, lamb: steaks, chops, roasts (rest 3 min) 63 °C · 145 °F

Fish and shellfish 63 °C · 145 °F

0 °C50 °C100 °C

Storage and danger zone

Keeping food safe from bacteria. Source: USDA.

Setting	°C	°F	Note
Fridge (at or below)	4	40	Official · USDA
Freezer	-18	0	Official · USDA
Danger zone	4–60	40–140	Official · USDA
Reheat to	74	165	Official · USDA

The danger zone (4–60 °C / 40–140 °F) is where bacteria multiply fastest. Limit food in this range to 2 hours or less (1 hour above 32 °C).

Sugar syrup stages

Exact by definition. Temperatures are for pure sucrose at sea level.

Stage	°C	°F	Used for
Thread	107–112	225–234	Thin syrup, spins a thread
Soft ball	112–116	234–240	Fondant, fudge, pralines
Firm ball	118–121	244–250	Caramels
Hard ball	121–130	250–266	Nougat, marshmallow
Soft crack	132–143	270–290	Butterscotch, taffy
Hard crack	149–154	300–310	Toffee, rock candy, lollipops
Caramel	160–177	320–350	Light to dark caramel; burns above 180 °C

Smoke points

Approximate — values vary by refining, age and brand. Use as a guide.

Butter ~150 °C

Extra virgin olive ~190 °C

Canola ~205 °C

Ghee ~230 °C

Refined avocado ~270 °C

0 °C150 °C300 °C

Boiling point and altitude

Approximate. Lower air pressure raises altitude and lowers boiling point.

Altitude	Metres	Boil °C	Boil °F
Sea level	0	100	212
500 m	500	98	209
1 000 m	1,000	97	206
1 500 m	1,500	95	203
2 000 m	2,000	93	200
3 000 m (Denver-ish)	3,000	90	194
4 000 m	4,000	87	189

Add roughly 5% more cooking time per 1 000 m of elevation. Leavening also acts faster at altitude — reduce slightly in baking.

Bread hydration

Typical ranges — actual results depend on flour brand, humidity and technique.

Bagel 50–57%

Dense, firm crumb

Sandwich loaf 60–65%

Soft, tender crumb

Baguette 65–70%

Open crumb, crisp crust

Country loaf 70–78%

Chewy, irregular holes

Ciabatta 75–85%

Very open crumb, slack dough

Focaccia 75–90%

Light, oily, very wet

50%70%90%

Cup weights

Approximate. Spooned and levelled. Values vary by packing method and brand.

Ingredient	g / US cup	Note
All-purpose flour	~125	Spooned and levelled
Bread flour	~130	Spooned and levelled
Wholemeal flour	~120	Spooned and levelled
Caster sugar	~200	—
Brown sugar (packed)	~220	Firmly packed
Icing sugar	~120	Sifted
Butter	~227	2 sticks
Rolled oats	~90	—
Honey	~340	—
Milk	~240	—
Water	~237	—
Cocoa powder	~85	Spooned and levelled
Desiccated coconut	~75	—
Rice (uncooked)	~185	Long-grain white
Breadcrumbs (dry)	~115	—

How to read the data

Three kinds of number, labelled as such

Official

Set by an authority

Safety temperatures and storage limits. Shown with the authority's name. Their guidance is the final word.

Exact

True by definition

Unit conversions such as Celsius to Fahrenheit or grams to ounces. Rounded for reading.

Approximate

A typical range

Smoke points, cup weights, hydration and altitude effects. Marked with "~" or a range, because they vary.

Questions about the kitchen data

: The USDA recommends a safe minimum internal temperature of 74 °C (165 °F) for all poultry — whole birds, ground poultry and leftovers. This temperature must be reached at the thickest part, not near bone. Source: USDA FSIS Chicken Guide.

USDA FSIS — Chicken from Farm to Table
: The danger zone is 4–60 °C (40–140 °F) — the range where bacteria multiply most rapidly. The UK Food Standards Agency and the USDA both advise keeping perishable food in this range for no more than 2 hours total (1 hour above 32 °C).

USDA — The Danger Zone
UK FSA — chilling food safely
: Smoke points vary by fat and how refined it is. Butter smokes around 150 °C, extra-virgin olive oil around 190 °C, canola around 205 °C, and refined avocado oil up to 270 °C. Values are approximate — see the Serious Eats smoke point explainer for why they vary.

Serious Eats — smoke points explained
: Hydration in bread is the ratio of water to flour, expressed as a percentage using baker's percentages. A 65% hydration dough has 650 g of water per 1 kg of flour. Higher hydration creates a more open crumb but requires more skill to handle. Sandwich bread sits at 60–65%; ciabatta at 75–85%.

The Fresh Loaf — baker's percentages
King Arthur Baking — hydration guide
: At higher altitudes, atmospheric pressure is lower. Water boils when its vapour pressure equals the surrounding pressure, so it boils at a lower temperature. At 3 000 m, water boils at approximately 90 °C instead of 100 °C. This means food takes longer to cook. The Engineering Toolbox boiling-point table has precise values by altitude.

Engineering Toolbox — boiling point of water

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