Post Tagged with: "stainless steel"

Does stainless steel really get rid of garlic smells? Round 2.


Some time ago we put the old wives’ tale that stainless steel gets rid of garlic whiffs to the test. The results were inconclusive and with hindsight the control probably wasn’t ideal. So we are having another go, this time with the backing of the Royal Society of Chemistry and a consortium of chemistry outreach folk from the Universities of Hull, Sheffield, York, Leeds, Bradford and Huddersfield (the Yorkshire Chemistry Outreach Group).

This is where you come in

We need as many people as possible to perform a simple experiment to test whether stainless steel really is an effective odour remover.

You’ll need: A clove of garlic. A knife. A blindfold. A plastic spoon and a stainless steel table spoon of about the same size.

What to do:

  1. Wash and dry your hands (so they don’t smell of anything to start with).
  2. Slice out a piece of garlic.
  3. Rub the freshly cut garlic between your hands for about 10 seconds.
  4. Under running water, rub one palm with the back of the stainless steel spoon for about 10 seconds. Then rub the other palm with the plastic spoon, again under running water, for 10 seconds (the plastic spoon is our control experiment). Make sure you remember which hand was rubbed with which spoon.
  5. Find a willing volunteer. Ask them to close their eyes or put a blindfold on – with their eyes closed, they are less likely to notice any signals from you about which hand has had what treatment.
  6. Hold a hand under their chin (that way each hand will be the same distance from the test subjects nose) and ask them to smell it. Then do the same with the other hand.
  7. Ask them which hand smelt more strongly of garlic.
  8. Let us know whether one hand smelt more than the other, or whether they smelt the same using this survey below.

What causes the whiff?

Garlic is packed with sulfur-containing chemicals, which are responsible for its characteristic taste and odour. Allicin, in particular, is thought to be the culprit most guilty of making your hands (and breath) pong, but it’s only created when two chemicals react – the enzyme alliinase and a sulfur-containing amino acid called alliin. These are held in separate portions within the cell walls of the garlic clove and only mix when the garlic is squished.

You can try it yourself – a bulb of garlic doesn’t smell of very much at all, but slice into it and smell again. When cells are crushed, the chemical reaction converting alliinase and alliin into allicin is almost instantaneous.

And when allicin degrades, it produces even more smelly sulfurous compounds, including diallyl disulfide. These all contribute to garlic’s characteristic aroma.

The chemistry of garlic.
www.compoundchem.com

How might stainless steel banish the pong?

The scientific data on whether the stainless steel trick actually works to get rid of stinky garlic hands is sketchy – although chemistry tells us that it might well work. Stainless steel is an iron alloy with a minimum of 10.5% chromium by mass. This layer of chromium is what makes stainless steel less likely to rust, corrode or stain. Chromium forms an oxide when it is in contact with air and water, making it more durable. It’s possible that this oxide layer could help to remove unwanted smells. The idea is that the sulfur-containing chemicals left on your hands after chopping garlic may form a chemical bond to the chromium oxide and cling to the surface of the soap, not to your hands, solving the smell problem. But we don’t really know.

We’ll need plenty of tests if we are going to be sure of our results, otherwise it’s just more anecdote. And we’ll get back to you, to let you know whether it’s worth forking out for stainless steel soap soon.

Over the next few months, we’ll be asking for more help from citizen scientists to check the efficacy of tips that may make flowers live longer, peeling a boiled egg easier and extend the burning time of candles. Check out the Hit or Myth blog to find out more.

The Conversation

Mark Lorch, Professor of Science Communication and Chemistry, University of Hull and Joanna Buckley, Materials chemist and science communicator, University of Sheffield

This article was originally published on The Conversation. Read the original article.

By November 24, 2016 7 comments Uncategorized

Garlic Challenge, the results show!

Back in October I posed a question: Is there any truth in the old wives tale that rubbing your hands on stainless steel gets rid of garlic smells? Various theories as to how steel may achieve this were posited. But I wanted to know if there was a real effect in the first place. Kitchen chemists everywhere helped answer this by taking part in a stinky citizen science challenge. And the results are, well, interesting.

Garlic

I asked people to conduct a quick experiment whilst prepping dinner. The task was simply to rub the palms of their hands with garlic. Then treat one hand with a wipe from a stainless steel spoon and the other with a wooden spoon. Finally participants asked some other poor soul to take a sniff of their hands and report on whether there was a discernible difference.

Thanks to everyone who took up the garlic challenge (especially the person who did their experimenting whilst cooking Christmas dinner).

And so to the results.

These were collected via surveymonkey, with the question “Which hand smelt more of garlic?” and the answer choices a) The hand rubbed with the wooden spoon, b) The hand rubbed with the stainless steel spoon, c) Couldn’t tell the difference.

44 allium lovers responded. Of those 17 thought the hand treated with the wooden spoon smelt more garlicky, 6 said the stainless steel treated hand was the stinkier. So far, so good. Looks like the stainless steel effect might be real. But here’s the rub, there’s still the other 21 responses, none of whom could tell the difference between the smelly hands.

 

Screen Shot 2013-12-31 at 10.48.37

 

So we’ve got results that are significantly different from an even distribution between the options (the two-tailed P value equals 0.0163 ,according to a chi squared test) . However, the stainless steel treatment seems to be only about 38% effective, assuming the wooden spoon is a good negative control. But maybe the abrasive, absorbent wooden spoon is also quite good at removing garlic smells? In which case the effectiveness of the stainless steel is an underestimate.

Oh well, sorry people, but it looks like I can’t really offer a definitive answer. In hind sight I think the experimental design could have been better. A before and after spoon treatment sniff test would have been a good idea. And maybe a better negative control was in order.

Looks like another round of experiments  could be in order. Or can anyone offer a better way of analysing the data (I suspect sensitivity vs specificity analysis might be more appropriate)?

By December 31, 2013 5 comments fun

Does stainless steel get rid of garlic smells?

Anyone fancy a quick food chemistry experiment to do whilst cooking dinner?

According to an old wives tale the best way to get rid of garlic smells on your hands is to rub them on stainless steel. You can even buy stainless steel ‘soap’ for that very purpose. This came up on twitter, the other day, and there was some speculation on the chemistry behind the phenomenon.

 

But before we get to the ‘how’ question maybe we should figure our if there is any truth in the anecdotes. Now for the experiment? Once your done please report results via the link at the bottom of the page.

Materials

A clove of garlic.

A knife.

A timer.

A wooden spoon and a stainless steel table spoon of about the same size.

Methods

1. Wash and dry your hands.

2. Cut the clove of garlic in half (don’t peel it, that way your fingers won’t pick up garlic smells when you hold it).

3. Rub the freshly cut surface on the palm of one hand for 10 seconds.

4. Rub the second piece of garlic on the palm of your other hand for 10 seconds (so ensuring an equally fresh and identical sized piece is used on each hand).

5. Rub one palm with the back of the stainless steel spoon and the other palm with the wooden spoon. Again for 10 seconds each. Make sure you remember which hand was rubbed with which spoon.

6.. Find a willing volunteer, ask them to close their eyes.

7. Hold a hand under their chin (thus keeping each hand  the same distance from the test subjects nose) and ask them to smell it. Then do the same with the other hand.

8. Ask them which hand smelt stronger of garlic.

 

Results
Please report them here.

Conclusions

I’ll  get back to you with a conclusion when enough results are in. Then we can start working on whatever chemistry involved.

Originally posted at www.t2ah.com

By October 26, 2013 3 comments fun, Uncategorized