is the alcohol drying method food safe

[mike scully]

hi i am just wandering is the alcohol method of drying bowls suitable for food safe items like salad bowls

 

[MichaelMouse]

Sure. Not as if the alcohol replaces bound water. It evaporates with the unbound, leaving the bound behind. Of course, if you skip the alcohol, you'll dry just as fast.

 

[robo hippy]

Just wondering MM, is this postulation/speculation/theory on your part, or have you, or any one else ever done a side by side measured test to prove this? Yes, I did grow up in the 'Show Me' state, and a lot of people swear by this method.

robo hippy

 

[MichaelMouse]

Matter of fact, yes. To do the closest comparison I ran sequential cubes of various species, did a soak versus a control and verified both shrink and time. Also put dye in the alcohol on a set to see how far things actually got in a few hours or a couple of days. Not much. Had a rather lengthy discussion on this forum with Dave the make-believe chemist which prompted the shrink comparison.

Drying was a no-brainer. The results were exactly what anyone who ever thought about how the whiskey got in his glass would have anticipated, even if he never had physical chemistry. I can't confirm your observation regarding the difficulty of sanding flashed surfaces, though I feel it's probably valid. In theory, they should behave as any other case-hardened surface behaves.

 

[Owen Lowe]

MM & RH,

I think the first question needs to be: What type of alcohol are we talking about?

I would think isopropyl, denatured, distilled, etc. would have a bearing on whether anything detrimental is left behind. In other words, let's assume nothing - compounded by the fact that Mike Scully is asking from Ireland and alcohol may mean something different than here in the US - or not...

 

[mike scully]

thanks good to no its food safe i am thinking about using methanol(denatured alcohol) this type of alcohol is alright isnt it for salad bowls better off to be sure with theses things dont want to kill any customers

 

[odie]

Matter of fact, yes. To do the closest comparison I ran sequential cubes of various species, did a soak versus a control and verified both shrink and time. Also put dye in the alcohol on a set to see how far things actually got in a few hours or a couple of days. Not much. Had a rather lengthy discussion on this forum with Dave the make-believe chemist which prompted the shrink comparison.

Drying was a no-brainer. The results were exactly what anyone who ever thought about how the whiskey got in his glass would have anticipated, even if he never had physical chemistry. I can't confirm your observation regarding the difficulty of sanding flashed surfaces, though I feel it's probably valid. In theory, they should behave as any other case-hardened surface behaves.

Mike Scully: My apology, but I have no idea if introducing alcohol into the wood will effect suitability for food use.

MM: From my point of view, your post raises more questions than it answers........Just wondering if you can provide a link to the discussion between you and "Dave the make-believe chemist"......?

ooc

 

[mike scully]

sorry my mistake i am using methylated spirits not methanol

 

[MichaelMouse]

Language difference. Meths (methylated spirits) rather than "denatured alcohol." The alcohol evaporates. It is not retained by the wood. Give it a few days past what the nose can detect to clear yourself of doubt. You could also remind yourself that the treatment for methanol poisoning is - ethanol. Take a dram or two as a prophylactic measure before dinner!

Methanol is used as a denaturant because it is almost impossible to differentially distill out of the ethanol mixture. As we know, this does not apply to ethanol/water mixtures, where ~95% ethanol (check "azeotrope") can be obtained by careful distillation. In moonshining, the majority of water remains behind in the primary pot of the still, with the "thump barrel" enriching the remainder. Evaporation short of boiling works the same way, which is why you might as well save your money on methylated (denatured) spirits.

Note, as well, that whiskey produced from the still (or wine by simple fermentation) is aged in wood, where the alcoholic content is only mildly reduced by the angels, not massively by retention in the wood.

 

[KellyDunn]

Mike, I would think cheaper methods of drying are available to you. I use a commercial wax type wood seal for the outside of bowls. Others use paper or plastic bags and reverse the plastic bag each day. Lots of drying methods. One will work for your climate. I would agree that the alcohol will mean nothing to the finished work. Since you want food safe know that all finishes (varnish,Poly mixes, various oil based finishes, epoxy,etc)when cured are food safe. Most oils will go rancid with time. Mineral oil is cheap and works well. The bowl will look bad though. If you build up any finish other than epoxy it will slowly develope cracks where moisture will get to the wood and make a mess. Will not happen overnight, but it will happen if the piece is used. I do a polyurethane mix and buff it back to the wood. That way I have a hard finish inside some of the wood pores. I give it a coat of ren wax and buff that. If the bowl is to be used I recomend a bit of mineral oil now and again. And also that the bowl get hand washed with soap and wather and dried. Not allowed to sit in a sink. The poly mix keeps the bowl looking very good for a long time.

 

[n7bsn]

Just wondering MM, is this postulation/speculation/theory on your part, or have you, or any one else ever done a side by side measured test to prove this? Yes, I did grow up in the 'Show Me' state, and a lot of people swear by this method.

robo hippy

I know people that have, like Fred Holder that did a side-by-side test with black walnut taken from the same tree, that found no difference in the drying time between the two

I also know people that have found there, with the woods they tried, they found a difference in drying time.

A couple of years ago I had occasion to discuss this with a wood-products professional that had knowledge in this area. What he told me was basically sometimes it worked, sometimes it doesn't. Some species were more likely to work, and some less, but this was not always true.
They also found that, given the cost of the DNA, the unknowns in controlling the process it was not cost-effective.

 

[Jean Turner]

This article may be of interest in judging whether it is 'food safe' or not:
http://en.wikipedia.org/wiki/Denatured_alcohol

 

[MichaelMouse]

A couple of years ago I had occasion to discuss this with a wood-products professional that had knowledge in this area. What he told me was basically sometimes it worked, sometimes it doesn't. Some species were more likely to work, and some less, but this was not always true.
They also found that, given the cost of the DNA, the unknowns in controlling the process it was not cost-effective.

Well, I think your friend might have been a bit more friendly than forward. Since dry kilns are consumers of heat, there would be no problem with redistilling, perhaps at a lower cost than applying heat to energize the process of speeding moisture from the wood. No barrier there.

Experiments have to have controls. Fred did a sort-of side by side with turnings, which is why he obtained the result science would have predicted. I did full side-by side with same species/grain orientation and dimension. Results as predicted. Can't speak for others.

 

[robo hippy]

Kelly,
After a lot of using of mineral oil, I came to the conclusion that the only thing it really does for the wood is give it that wet look for a day or two, then it is gone.

As far as all oils going sour, that is not the case in my observations. I can remember hearing the 'never use olive oil because it WILL go sour' when I was starting out. Then I ran into a guy at a show who used only olive oil. In talking to him about it, his customers seldom had problems. The biggest thing to me is that the bowls need to be in the open where they can breathe. We all know about not leaving wet wood sealed in a plastic bag. With a curing oil, like walnut, once it is dry and cured, it wll not go sour. I had one bowl for 10 years, used it almost daily before it eventually cracked off a ring shake crack that was not visible to my untrained eye. When bowls do get funky, it is because they are locked away out of sun and light, or, and this is the important part, there is food/oil/crud build up on the bowl that is allowed to sit. I never reoil my personal bowls after the oil has set. I do rinse and scrub them out every time I use them. If I start to feel some build up, that is when I take some soap to them, or a wedge of lemon or lime, which do the same thing. So, if the bowl goes sour, it is from not taking care of it properly.

As MM commented to me years ago on the Google woodturners forum, incomplete oxidation. You have to be careful with non drying oils. No build up!

robo hippy

 

[KellyDunn]

RH,if a person uses soap and water and dries the bowl after each use then true any oils used would not be allowed to sit. Many folks just take a paper towel and wipe the bowl out. Leaving the oils to slowly go rancid and make a sticky mess. If each bowl owner took the time to do what I or you do there would never be any problems. I gave a bowl to a couple. They asked how to take care of it. At the time I was using mineral oil so said put a little on when the bowl looks dry. I did not see them for a couple years. Not only had they not even used the bowl but they soaked it in mineral oil and wrapped it in a plastic bag. The oil reacted to the tannins in the wood I guess but what bad smelling mess. That is the 1st I had seen mineral oil go sour. At that point I suggested they put the bowl through the dishwasher and never wrap it up again. Since I am in the tropics I see stuff happen to utilitarian wood items that would gag flies. I good number of my bowls are with friends in Colo. Zero problems.

 

[Jim Rinde]

Kelly: Mineral oil is TOTALLY inert. It will not react with anything while in a plastic bag. Probably what went wrong is that the wood rotted in the moist enviroment inside the plastic bag. Minerial oil is safe and non-reactive.

 

[MichaelMouse]

Kelly: Mineral oil is TOTALLY inert. It will not react with anything while in a plastic bag. Probably what went wrong is that the wood rotted in the moist enviroment inside the plastic bag. Minerial oil is safe and non-reactive.

It is a non-polar solvent, and oil-soluble materials can shelter in it and decay just as water-soluble materials foul the water they are in. Give the bacteria one final osmotic thrill with some surfactant, then rinse. It will emulsify and wash the oil away, but if you can always add more....

 

[KellyDunn]

Jim, its the ONLY time I have seen a nasty thing with mineral oil so both you and Mr. mouse are probably correct. I used mineral oil on all my work for a few years. I still get one back to refinish now and again. They look terrible. Most are so old and dry and nasty looking I refinish them in my poly mix. The owners are thrilled when they get it back. I am in my 24th year as a full time turner and still experiment. I do however not use epoxy like you do. But when the conversation comes up I do mention your name.

 

[robo hippy]

After pondering this a while, I think another key to keeping bowls from going sour is to use a penetrating oil that will cure. I think back to a maple bowl I had that was walnut oiled. I was in a rainy show here in western Oregon, and it got some drip marks on it. Well, some weeks later I tried to reoil it to remove or cover the drip mark. It didn't work as the drip mark was sealed in. If you have a curing oil, it will keep others from penetrating, and you then only have to remove the surface oil. Not too difficult. I only rinse and use a scrubby, and most of the time just rinse and wipe with a napkin or paper towel.

robo hippy

 

[Bart Garber]

The only answer to the question is , yes. No more no less.

 

[Clifton C]

Bart,
What's the fun in that ???