I have a meat grinder with a few aluminium parts. Hand-washing isn’t *too *bad, but I’d like to put some parts in the dishwasher. Since it only comes out once every four or five months or so, and even then only when it’s just us in the kitchen, I don’t care whether it’s shiny silver, dull grey or oxidized black. I do care, though, whether it’ll dissolve in the dishwasher, do something nefarious when my back is turned (e.g. deposit aluminium on other items in the dishwasher), or taint our delicious ground meats.
You are likely to get corrosion - I’m not going to guess how much, or its chemical composition.
Dishwasher detergent, since it is not intended to human contact, is nasty stuff. There are various kinds of AL, to add to the crap shoot.
Findidentical parts at Good Will or some such Thrift shop p- having $5 in your expeimentation is not as bad as rendering the entire machine unusable.
FWIW- I would NOT consider it, and I am a Slob First Class.
It will not dissolve, or do anything nasty. Rather the reverse: the surface will oxidise, gaining oxygen.
However, my experience is that normal-weight aluminium baking pans will pit, and then the pits will eat through, and then you will have holes in your aluminium baking pans.
How long this would take to happen with meat-grinder parts, washed rarely, and if it will affect the grinding and bearing surfaces, I couldn’t say.
My approach has been to wash by hand, and not complain when other people wash in a dishwasher, or with laundry soap.
Al has the property of being able to react with both alkalis and acids. Passivation by oxide coating means reaction with acid is slow in most environments. However, you can get a good reaction between aluminium and caustic soda releasing large amounts of hydrogen gas.
Aluminium also suffers greatly in the presence of chloride ions. The oxide coating is not self-healing in a certain concentration of Cl- and so corrosion can occur at that site – propelled by a large electrical potential difference. The presence of a large cathode and small anode means that the reaction is highly localised and quite fast ie, pitting.
I am not up with the play with the constituents of dishwasher detergents. However, I believe they are quite caustic – hence the requirement to keep aluminium well away from them.
On the other hand, if you don’t overdo the quantity of detergent used and if the Al does not come into direct contact with the powder and if it is in a position where it gets rinsed really thoroughly then you might find that you get away with it.
There is a danger. Not heard of it happening but it is possible.
2 Al + 2 NaOH + 6 H2O → 2 Na[Al(OH)4] + 3 H2
Dishwasher powder contains NaOH… this reaction causes the pitting… the dissolving of the aluminium into the water.
The aluminium oxidises, and while the salt contains some hydrogen , there is hydrogen gas evolved.
Really? :dubious: Yet surely one of the commonest used of aluminium pans is the boiling of vegetables, usually with some added salt (NaCl). Certainly I have done lots of it, yet my aluminium pans seem to have survived fine.
Yes you can, if you pick the right dishwashing detergent. Here’s a consumer report highlighting which detergents do what to aluminum :
What if he puts them in the dishwasher without detergent? Would it help get the nooks and crannies clean through blasts of super hot water, better than hand-washing?
We have a meat grinder that gets used every few years. I wash it then soak it in a pot of boiling water; air dry then pack away.
The grinder parts probably develop an ugly powdery scale in the dishwasher. Unless you scrub this off with Brillo, the crud is apt to transfer into the meat.
Of course, needing to scrub it off defeats the whole idea of running them in the dishwasher to avoid hand-washing.
Thanks, so it’s hand-washing for the duration. Any guesses at why the parts (feeder hopper, grind plates) are aluminium instead of steel? Is it less expensive to manufacture? Easier on the …? Designer’s choice?
Really.
http://www.kau.edu.sa/files/0008822/researches/55731_26032.pdf
http://www.doiserbia.nb.rs/img/doi/0352-5139/2008/0352-51390805561L.pdf
AFAIK, it’s a lot easier to cast and machine aluminum than stainless steel, especially in the shapes and thicknesses needed for a food grinder.
Not saying it can’t be done in stainless, but you probably wouldn’t want to pay for it.
OTOH, I’d be surprised if the actual grinding components are not steel. I’ve got an ancient hand-cranked food mill with an aluminum body and steel plates and a modern Kitchen Aid attachment that’s got a plastic body and steel grind plates. The old one’s plates are not stainless, so if we’re ever in a mood to use it, the parts go into a warm oven to dry after washing. The KA’s parts are mercifully dishwasher safe and non-rusting.
I will add that pitting and crevice corrosion are what we might term runaway processes. Nothing happens for a long time. Then the oxide surface is broken and the reaction happens very quickly and is very localised.
Pitting via chlorides is more of a problem in acid environments and is exacerbated where there are little crevices or dirty regions that are undisturbed where concentrations of reactants can locally be rather high. So don’t leave tomato salsa in your aluminium pots overnight. Pitting and crevice corrosion can be mitigated against easily by rinsing with water.
That said, I think the caustic nature of dishwasher powders is more likely to be an issue and the corrosion mechanism is likely to be different. You aren’t going to get the same pitting but you will get a degradation of the protective oxide coating which may lead to a visual brightening of the surface but may also lead to scale build up which may then lead to other forms of corrosion.
Hence, small amount of detergent. Effective rinsing. Short cycle. See what happens. If no visible change then you are probably in the clear. If it comes out really bright the first time you try it then you probably want to discontinue the use of a dishwasher for this item.
(Note that the specifics of corrosion mechanism and rate are dependent on the exact alloy used as well as its physical geometry. What works for one kitchen utensil may not work for another.)