In this article
Start with the appliance available at lunch. Black+Blum's Original Lunch Box follows a familiar microwave route, the standard Stainless Steel Lunch Box is for cold meals or oven reheating, the Microwavable Steel Food Box has its own strict microwave procedure, and the Food Flask carries a meal that was heated or chilled before leaving home.
Match the container to where the meal changes temperature
| Format | Published capacity | Heating route | Best fit |
|---|---|---|---|
| Original Lunch Box | 1 L, plus small inner pot | Microwave with lid removed; manufacturer sets a two-minute maximum at a time | Work or school with a conventional microwave |
| Stainless Steel Lunch Box | 1 L | Base and divider may go in the oven; lid stays out; not microwave-safe | Cold meals or reheating in an oven |
| Microwavable Steel Food Box | Size-specific | Microwave only under the exact Black+Blum instructions | People who want a steel vessel and control the microwave setup |
| Food Flask | 400 ml | Pack already hot or cold; no microwave | Routes with no reheating appliance |
Capacity is a container measurement, not a meal prescription. Stage the usual lunch, utensils and bag before choosing.
Original Lunch Box: familiar reheating workflow
The Microwavable Original Lunch Box 1L uses a non-steel base. Black+Blum's instructions permit microwaving with the lid removed for no more than two minutes at a time, followed by stirring before another interval. The box includes an inner dish and a small sauce pot, which can keep toppings or dressings separate. The same instructions say the lid is not dishwasher-safe, so count hand washing and drying in the routine.
This is the clearest choice when a normal microwave is available and the user wants to reheat the meal in its main container. Confirm that the workplace or school allows personal containers and that the box fits the appliance.
Stainless Steel Lunch Box: no microwave ambiguity
The Stainless Steel Lunch Box 1L is 304 stainless steel, with a fork and divider. Black+Blum's care instructions permit the base and divider in the oven but require the silicone-sealed lid to stay out; the product is not microwave-safe. The lid and silicone strap are hand-wash only, while the remaining pieces may go in the dishwasher. Choose it when cold food, oven reheating or material preference matters more than microwave convenience.
Do not transfer the microwave claim from another Black+Blum line to this one. “Stainless steel” is a material description, not a heating instruction.
Microwavable steel: read the appliance rules first
Black+Blum's microwavable steel boxes are a specifically engineered product line. Its official Meal Prep Box instructions and FAQ require one box at a time, the lid unlocked, no foil or cutlery, and short heating intervals before stirring. They also exclude some older 915 MHz microwaves and tell users not to microwave a badly dented or scratched box. The three-size steel box set is a direct shopping path when all three sizes have a defined weekly job.
If the appliance frequency cannot be confirmed, or a shared microwave policy prohibits metal, choose another format. Before putting the steel set in a microwave, use the step-by-step microwave guide for the full setup and stop conditions.
Food Flask: transport temperature rather than reheat
The Food Flask 400ml is designed to carry food already hot or cold. Black+Blum rates the flask for up to six hours hot and eight hours cold and instructs users to pre-condition it with hot or cold water for about five minutes. Those are manufacturer insulation-performance claims, not food-safety holding times or a guarantee of serving temperature: Health Canada advises keeping hot food at or above 60 C and cold food at or below 4 C. The flask is not microwave- or dishwasher-safe, and its instructions exclude keeping milk products or baby food warm or cool.
Check fit before checkout
- Name the actual heating appliance: none, conventional microwave or oven.
- Measure the meal and bag, including inner pots, fork and any drink.
- List which pieces must be hand washed and where they will dry.
- Confirm the exact product line on the product page and care instructions.
Choose for the repeated meal, not the edge case
For a desk lunch reheated most days, the Original Lunch Box offers the least unusual microwave workflow. For salads, sandwiches and oven-reheated food, the standard steel box avoids the special microwave decision. For soup or stew eaten away from appliances, the Food Flask keeps the heating step at home. The microwavable steel line earns its place only when its appliance rules can be followed consistently.
Do not choose the largest or most technical format for a rare meal. Let the most frequent lunch use decide the primary container, then handle occasional soups, oven meals or cold lunches with a suitable vessel already owned.
Account for the small pieces
Dividers, forks, sauce pots, seals and lids change both usefulness and cleanup. Pack a real meal, shake only as the manufacturer permits, then unpack over a counter. Confirm whether a sauce pot has a defined home, whether the fork remains clean, and whether the lid can dry without trapping water. Replacement availability matters most for the part whose loss stops the container from travelling.
Know the exits
- Choose glass or another microwave-safe non-steel box if shared-appliance rules are unclear.
- Choose a plain insulated food jar if one wet main is the entire job.
- Choose a lighter bento if the filled steel system is uncomfortable to carry.
- Keep an existing container if the new format adds no repeated heating or packing advantage.
Black+Blum products can look closely related. Make the choice from the printed product name, the available appliance and the exact instructions, not from colour, shape or a broad claim about steel.
