Optimize my hypothetical ice cream scoop!
July 17, 2023 2:38 AM Subscribe
From a thermodynamics perspective, what makes a better ice cream scoop, steel or aluminum?
Say I want an ice cream scoop made of either steel or aluminum I want to heat it up to make it easier to scoop the ice cream and I want it to stay warm long enough for several scoops.
Based on what little understanding of physics I have, aluminum is an ideal material (oxidation aside) for melting ice cream because it has both a high specific heat capacity and high thermal conductivity; it will lose much heat readily to the cream. The only problem is, aluminum may be too good at this and will cool and freeze too quickly.
Steel, on the other hand, is three times as dense as aluminum, but its specific heat capacity is only half, so it will actually store more heat than aluminum and dissipate it more slowly. Maybe it won't scoop as easily, but it'll last longer.
(I suppose I should consider the possibility that faster scooping (aluminum) gets me more ice cream faster than slower, longer-duration scooping (steel) so that it all balances out anyway?)
Let's assume for the sake of argument that:
a) The shape and dimensions of both hypothetical scoops are identical.
b) This question is not keeping me up at night, nor inspired by a know-it-all teenager.
Say I want an ice cream scoop made of either steel or aluminum I want to heat it up to make it easier to scoop the ice cream and I want it to stay warm long enough for several scoops.
Based on what little understanding of physics I have, aluminum is an ideal material (oxidation aside) for melting ice cream because it has both a high specific heat capacity and high thermal conductivity; it will lose much heat readily to the cream. The only problem is, aluminum may be too good at this and will cool and freeze too quickly.
Steel, on the other hand, is three times as dense as aluminum, but its specific heat capacity is only half, so it will actually store more heat than aluminum and dissipate it more slowly. Maybe it won't scoop as easily, but it'll last longer.
(I suppose I should consider the possibility that faster scooping (aluminum) gets me more ice cream faster than slower, longer-duration scooping (steel) so that it all balances out anyway?)
Let's assume for the sake of argument that:
a) The shape and dimensions of both hypothetical scoops are identical.
b) This question is not keeping me up at night, nor inspired by a know-it-all teenager.
It’s not as though you’re starting with a warm scoop and scooping ice cream until the scoop becomes cold. The scoop will warm up in between scoops—either by being placed in a container of warm water, as ice cream shops do, or just by having the relatively warm handle transfer thermal energy to the bowl of the scoop. This favors a scoop with high thermal conductivity and a design that facilitates transfer of thermal energy into the bowl, which is why Zeroll scoops are so highly regarded. Short answer: aluminum.
posted by slkinsey at 4:16 AM on July 17, 2023 [3 favorites]
posted by slkinsey at 4:16 AM on July 17, 2023 [3 favorites]
Best answer: Former Haagen-Dazs scooper here to say that the "dipping well" where the scoops go between servings was room temperature water -- it rinsed the scoop clean to prevent flavors mixing, but wasn't heated at all.
And we always used aluminum scoops, not steel: I (also) believe the aluminum ones conduct heat more readily, so they come back sooner to being "warm" after contact with the ice cream.
posted by wenestvedt at 6:34 AM on July 17, 2023 [2 favorites]
And we always used aluminum scoops, not steel: I (also) believe the aluminum ones conduct heat more readily, so they come back sooner to being "warm" after contact with the ice cream.
posted by wenestvedt at 6:34 AM on July 17, 2023 [2 favorites]
Not only is there the room temp water, but the heat of the scooper's hand that warms up the system. I'm joining the majority on this opinion ;)
posted by advicepig at 7:06 AM on July 17, 2023 [1 favorite]
posted by advicepig at 7:06 AM on July 17, 2023 [1 favorite]
Response by poster: Thanks for the responses so far. Aluminum is probably better in the practical case.
How about a theoretical case where the scoop is not being "recharged" by the heat of the user's hand and is not being returned to warm water (let's say the ambient air temperature isn't contributing anything). Does steel work better as a slow-release reservoir of heat, or does aluminum still win (or does it require too much differential calculus to determine?)
posted by klanawa at 8:27 AM on July 17, 2023
How about a theoretical case where the scoop is not being "recharged" by the heat of the user's hand and is not being returned to warm water (let's say the ambient air temperature isn't contributing anything). Does steel work better as a slow-release reservoir of heat, or does aluminum still win (or does it require too much differential calculus to determine?)
posted by klanawa at 8:27 AM on July 17, 2023
May I recommend the copper Short'ning scoop for your consideration? Not dishwasher safe, tho.
posted by fiercekitten at 9:10 AM on July 17, 2023
posted by fiercekitten at 9:10 AM on July 17, 2023
Best answer: Does steel work better as a slow-release reservoir of heat....
Not really. Once steel gets cold, it stays cold -- which would make the ice cream stick to the scoop.
A slightly-warm aluminum scoop allows the ice cream portion to curl smoothly and then drop freely into the cup/cone.
posted by wenestvedt at 9:14 AM on July 17, 2023 [2 favorites]
Not really. Once steel gets cold, it stays cold -- which would make the ice cream stick to the scoop.
A slightly-warm aluminum scoop allows the ice cream portion to curl smoothly and then drop freely into the cup/cone.
posted by wenestvedt at 9:14 AM on July 17, 2023 [2 favorites]
Best answer: It's not particularly useful to think of these things in terms of temperature. You could have a scoop with a thick-walled bowl at 100 degrees and one with a thick-walled bowl at 70 degrees, and the thick-walled scoop will work better. That's because, even though the thin-walled scoop is at a lower temperature, it's holding more thermal energy.
Here's a way of thinking about it: The premise is that the bowl of the scoop transfers thermal energy to the ice cream as it is scooped, which has the effect of raising the temperature of the ice cream at the scoop-ice cream interface, which in turn facilitates easier scooping. This brings up several questions, but the most basic are: (i) how does thermal energy get into the bowl of the scoop, and (ii) where does it come from?
The answer to (i) is thermal conduction, and I'll circle back around to that, but the answer to (ii) is a little bit more complicated and depends on the design of the ice cream scoop. Generally speaking the thermal energy in the bowl of the scoop will either come from ambient conditions (i.e., room temperature) or it will have to be transferred from elsewhere in the scoop. This is the fundamental premise of the classic Zeroll scoops I linked above: thermal energy is transferred from the handle of the scoop into the bowl of the scoop (which happens regardless of whether the scooper's hand transfers thermal energy into the handle). It is highly unlikely, however, that a similar design would be machined out of stainless steel, if only because it would be prohibitively expensive. The more common design for steel is the "disher" type scoop in which a thin-walled bowl with an internal scraper is connected to a slender steel shaft embedded in a plastic handle. It should be apparent that there is far less thermal energy available to the bowl of a disher than the bowl of a scoop, and its obvious to anyone who's tried to scoop cold ice cream with a disher that it's not very easy.
But let's suppose someone does machine a scoop in the Zeroll design out of steel. That scoop would be quite a bit heavier than the aluminum version and would contain quite a bit more thermal energy. Wouldn't this make the steel version work better? Most likely, no. The reason for this is in the answer to (i) above: thermal conductivity. The thermal conductivity of stainless steel is terrible, and as a result the steel scoop won't be very good at transferring thermal energy from the handle to the bowl of the scoop. It's more likely that the bowl will cool down fairly quickly and stay that way. Aluminum, on the other hand, has very good thermal conductivity and even though the aluminum scoop won't hold as much thermal energy compared to the steel one, it will be much more effective at transferring what thermal energy it does have into the bowl of the scoop (and then into the ice cream).
posted by slkinsey at 10:33 AM on July 17, 2023 [3 favorites]
Here's a way of thinking about it: The premise is that the bowl of the scoop transfers thermal energy to the ice cream as it is scooped, which has the effect of raising the temperature of the ice cream at the scoop-ice cream interface, which in turn facilitates easier scooping. This brings up several questions, but the most basic are: (i) how does thermal energy get into the bowl of the scoop, and (ii) where does it come from?
The answer to (i) is thermal conduction, and I'll circle back around to that, but the answer to (ii) is a little bit more complicated and depends on the design of the ice cream scoop. Generally speaking the thermal energy in the bowl of the scoop will either come from ambient conditions (i.e., room temperature) or it will have to be transferred from elsewhere in the scoop. This is the fundamental premise of the classic Zeroll scoops I linked above: thermal energy is transferred from the handle of the scoop into the bowl of the scoop (which happens regardless of whether the scooper's hand transfers thermal energy into the handle). It is highly unlikely, however, that a similar design would be machined out of stainless steel, if only because it would be prohibitively expensive. The more common design for steel is the "disher" type scoop in which a thin-walled bowl with an internal scraper is connected to a slender steel shaft embedded in a plastic handle. It should be apparent that there is far less thermal energy available to the bowl of a disher than the bowl of a scoop, and its obvious to anyone who's tried to scoop cold ice cream with a disher that it's not very easy.
But let's suppose someone does machine a scoop in the Zeroll design out of steel. That scoop would be quite a bit heavier than the aluminum version and would contain quite a bit more thermal energy. Wouldn't this make the steel version work better? Most likely, no. The reason for this is in the answer to (i) above: thermal conductivity. The thermal conductivity of stainless steel is terrible, and as a result the steel scoop won't be very good at transferring thermal energy from the handle to the bowl of the scoop. It's more likely that the bowl will cool down fairly quickly and stay that way. Aluminum, on the other hand, has very good thermal conductivity and even though the aluminum scoop won't hold as much thermal energy compared to the steel one, it will be much more effective at transferring what thermal energy it does have into the bowl of the scoop (and then into the ice cream).
posted by slkinsey at 10:33 AM on July 17, 2023 [3 favorites]
* I, of course, meant to write, "You could have a scoop with a thin-walled bowl at 100 degrees" and "even though the thick-walled scoop is at a lower temperature, it's holding more thermal energy."
posted by slkinsey at 10:39 AM on July 17, 2023 [2 favorites]
posted by slkinsey at 10:39 AM on July 17, 2023 [2 favorites]
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So the heat would be maintained by the gel (and recharged putting it back into a tall container of warm water, but never put it in the sanitiser). And you get the good benefits of the aluminium scoop spoon bit.
It always felt like it worked better than the regular 'domestic' steel ended scoop spoon with no gel handle thing. Even though the steel spoon had a sharper and harder edge so should have cut into the ice-cream better. But not being identical forms I can't be sure.
If commercial products for this task prefer aluminium, in my mind that's a sign it's better suited to the task, even more so with the add-ons that I imagine work better with aluminium than they would with steel.
But that is all experiential for me, not based on thermodynamic calculations.
posted by many-things at 4:05 AM on July 17, 2023 [3 favorites]