How the Five Compare on the Numbers
Clear ice is made by freezing slowly in one direction, and the figure that matters is how long that takes. True Cubes publishes 18 to 22 hours, FDDBI 24 to 30 hours and TINANA 30 to 36 hours. Luma Comfort is a powered machine and publishes 15 minutes to the first cubes and 40 lb of ice in 24 hours. ClearlyFrozen publishes no time and says freezer timing is not required.
Output per batch splits them the other way. ClearlyFrozen makes ten 2 inch cubes, FDDBI eight 2 inch spheres, TINANA eight 2 inch cubes and True Cubes four cubes at 2 by 2 by 2 inches. Luma Comfort is the heaviest of the five at 25.5 pounds because it is an appliance rather than a mold, and it is the only pick that needs a power outlet.
What the table will not tell you is how much freezer space each mold takes while it works, because the dimension fields cover the mold and its foam box together on two picks and the mold alone on others. It also will not tell you the clarity you actually get. Every listing describes the mechanism and not one publishes a measurement of how clear the finished ice is.
Time Is the Real Specification
Eighteen Hours, Thirty Six Hours, or Fifteen Minutes
True Cubes publishes the quickest mold figure, 18 to 22 hours for four cubes, and it is a genuine advantage because it means a batch started in the evening is ready the next afternoon. FDDBI publishes 24 to 30 hours for eight spheres and TINANA 30 to 36 hours for eight cubes, which means a batch started on Friday night is not reliably ready until Sunday.
Luma Comfort is a different proposition entirely. It publishes 15 minutes to the first cubes and 40 lb over 24 hours, because it freezes water in layers over a chilled tray rather than waiting for a freezer to work through a block. If you need clear ice on the day you decide you want it, four of these five cannot do that and one can.
What the Waiting Buys You
Slow directional freezing is why the molds take so long. FDDBI is the most explicit about how delicate the process is, telling you to stand the vessel on a flat surface, to minimize vibration, and specifically to avoid opening and closing the freezer door during the freeze. That is a real constraint in a household freezer and no other listing mentions it.
ClearlyFrozen goes the other way and states that its improved system does not require freezer timing, which is why it publishes no hour figure at all. Whether that is an advantage or a missing specification depends on how you read it: it removes the need to plan, and it also removes the only number in this category a buyer could use to plan.
Cubes, Spheres and How Many Per Batch
Ten Cubes Against Four
ClearlyFrozen makes ten 2 inch cubes in one mold and argues the point directly, saying it costs a fraction of products that make four cubes or even two. Against a batch that takes a day or more, cube count is the specification that decides whether you can serve a room. FDDBI and TINANA both make eight, and True Cubes makes four.
ClearlyFrozen also publishes something no other listing here does: alternative molds sold separately, one making twenty one cubes at 1.3 inches for smaller rocks glasses, another making six spears at 5 inches for highballs. The foam insulation box is shared between them, so the system extends rather than being replaced. That is the only modular arrangement in this pool.
The Shape You Actually Want
FDDBI is the only sphere maker among the five, producing eight 2 inch balls, and a sphere has less surface area for its volume than a cube, which is the argument for it in a whiskey glass. It is also the heaviest mold here at 3.53 pounds, with fields of 6.2 by 11.8 by 5.5 inches including its foam box.
Two more sphere makers were in this category and both were left out. They are stainless steel vacuum cup designs sold in packs of two, near identical to each other, and neither publishes a freeze time. One of them publishes a genuinely interesting detail, a silicone mold that lifts itself slightly as the freeze completes to make demolding easier, but two balls a batch could not compete with eight.
Foam Boxes, Vibration and Claims That Cannot Be Checked
The Part People Throw Away
Both ClearlyFrozen and FDDBI put a warning in capital letters on their listings: the foam box is not packing material, it is part of the product, do not discard it. That warning exists because the insulation is what forces the ice to freeze downward from the open top, pushing dissolved air into the reservoir below through holes in the base of the mold.
TINANA and True Cubes both work on the same principle and neither mentions insulation at all. TINANA describes a lid and tells you to fill each cavity close to it, and True Cubes says it mimics the freezing process found in nature with no special gadgets or tools required. Those are descriptions of the result rather than of the mechanism that produces it.
A Purification Figure and a Listing Made of Awards
True Cubes publishes the one hard purity claim in this pool, that its tray is proven to purify water by removing 98 percent of TDS and metals. Nothing on the listing says who proved it or how it was measured, and total dissolved solids removal is a property of the freezing process rather than of the tray, so the figure is attributed here and not endorsed.
ClearlyFrozen’s first two feature bullets are not specifications at all. They are a rating and a list of publications that have recommended the product, which pushes the actual mechanism down to the fifth bullet. The product underneath is the most capable mold in this group, which makes the choice of what to lead with an odd one.
Which One Fits Your Kitchen
You want clear ice today, not tomorrow. Luma Comfort publishes 15 minutes to the first cubes and 40 lb over 24 hours, with selectable ice size, indicator lights, an insulated storage bin and meltwater that drains back for the next batch. It needs a power outlet and weighs 25.5 pounds.
You are serving a room, not a glass. ClearlyFrozen makes ten 2 inch cubes in one batch, states that freezer timing is not required, and offers separate molds for twenty one 1.3 inch cubes or six 5 inch spears using the same insulation box. Published at 1 pound.
Spheres for whiskey rather than cubes. FDDBI makes eight 2 inch balls in 24 to 30 hours, with a foam insulation box and the only vibration warning in the pool, telling you to keep the freezer door shut while it works. It is the heaviest mold here at 3.53 pounds.
Eight cubes and you can wait. TINANA makes eight 2 inch cubes in 30 to 36 hours, in a silicone tray with a lid, and tells you to fill every cavity close to that lid. The longest wait in this group, for the same cube count as the sphere maker.
The shortest wait from a mold. True Cubes publishes 18 to 22 hours for four 2 by 2 by 2 inch cubes from ordinary tap water, with no additives or extra tools needed, in BPA free silicone at 1.88 pounds. Fewer cubes, but ready in under a day.
What We Could Not Verify
Six things a clear ice buyer would want from these five listings and cannot get.
- One of the five publishes no freeze time at all, stating instead that freezer timing is not required, which removes the only figure a buyer could plan around.
- No listing publishes any measurement of how clear the finished ice is. All five describe a mechanism and none quantifies the result.
- True Cubes claims its tray removes 98 percent of TDS and metals without saying who measured it or how, on a property that belongs to the freezing process rather than to the tray.
- Luma Comfort lets you choose an ice size and never publishes what those sizes are, so its cubes cannot be compared with the 2 inch molds here.
- Two of the five publish nothing about insulation, though both rely on the same directional freezing that makes the other two warn you not to throw the foam box away.
- Two of the dimension field sets cover the mold and its foam box together, so freezer space needed cannot be compared consistently across the five.
