Yet another chemistry question - Mark/Stuart, help please !

I can't tell you how cool it is that we have all you brainy chemists on this board !

Hoping you can shed some light on my vanilla extract, please ? I'm making my own vanilla extract - process is to split the pods down the middle and macerate them for an extended period in a neutral spirit, such as vodka. In my internet research though, I've come across a couple of people who suggest that there needs to be a % of water in there as well - does this sound reasonable ? The suggestion by one was that the water actually extracts different things from the vanilla pods, causes the end product to darken more, and produces a different aroma. I have one small bottle with a vanilla pod, mostly vodka and a little water as a test, but it doesn't seem to be doing anything different from all the others, thus far.

I guess I'm curious as to the chemistry, if any, behind this ? Thanks...

Cheers, Celia

This is probably closer to Mark's specialty than mine, but I will note that vodka already is 50% water. In extractions, the solvent is chosen depending on what you're trying to extract. Remember the old saw about oil and water not mixing?

Polar solvents like water tend to dissolve polar molecules and salts, non-polar solvents like ethers or simple hydrocarbons tend to extract non-polar molecules like fats. Ethanol is much less polar than water (though much more polar than, say, ether or pentane), so it will dissolve things that water won't and vice versa. Temperature is also a factor- any kitchen chemist knows that hot solvents will dissolve things better than cold solvents; that's the trick used to make rock candy: the sugar is dissolved in hot water to nearly saturation, then it falls out of solution and crystallizes when the temp is lowered.

Looking at the vanillin molecule, one can see that it is an alcohol, so I'd expect it to have a higher solubility in ethanol than in water. Varying the water content and temperature will change the amount of other compounds extracted which will, in turn, affect aroma and flavor, distinguishing natural vanilla extract from wood or petroleum-derived vanillin. If I had to guess, there's a ratio of water and ethanol that people have found to be optimum for flavor, but I honestly don't know what that is.

FWIW I'm a biochemist - chemist and I'm around.

But I doubt I can add much to what Stuart has already said. Unless you have a greenhouse full of vanilla orchids (??) it seems like a rather quixotic project, since the last time I bought vanilla pods I think I paid something like $4.00 for two of them. To make a whole bottle of extract you would want 20 or 30 pods, wouldn't you? Speaking from a standpoint of complete ignorance (on my part)...

The vanilla itself should be very water soluble. Are you ONLY splitting the pods or are you whacking the heck out of them and chopping them up into 100 pieces??

Frank

Cool, Frank, another chemist ! Thanks for putting your hand up..

I found a bulk special on vanilla beans at a local (legit) food supplier - not ebay - and the pods are beautiful, plump Tahitian beans. They're costing me about $1 each. I'm not making the vanilla extract to save money really, it's just that now that I have all these pods, I can afford to play. I have 9 split beans in a 700ml bottle of vodka, which is turning amber coloured really quickly. The vanilla aroma was quite evident after just a couple of days ! I'm not chopping up the beans, purely because that looks messy (how unscientific !). I'm keeping them in a dark cupboard and shaking them every day (at the moment - the excitement might wear off over the next few months..)

Here are a few links :

http://www.vanilla.com/showcase/docs/va ... tract.html
http://www.kitchenproject.com/vanilla/4 ... xtract.htm
http://www.travelerslunchbox.com/journa ... nilla.html

Why am I trying to make my own ? Well, I'm on a bit of a quest to have as much homemade as I can. We bake all our breads (yeasted and sourdough), cookies and cakes, make our own greek yoghurt, and try to have as few processed foods as possible. The exception here are deli foods - hams, proscuittos, turkey, antipasto and cheeses - which form the basis of a lot of lunches. We used to make our own pasta, but that got too laborious. So I guess vanilla extract is just the next thing on the list to try....

Cheers, Celia

Stuart, thank you ! That all makes sense to me (if I read it slowly ). One question - if the vodka is already 50% water, does the water component in that not already extract the other compounds ? In other words, if there's already water in the vodka, what advantage is there to add more (other than the ratio aspect) ? Or is the water locked up with the ethanol and therefore behaving differently ? Hmm... that wouldn't make sense, would it ? (Chemistry was never my forte).

Cheers, Celia

Well, I'm on a bit of a quest to have as much homemade as I can. We bake all our breads (yeasted and sourdough), cookies and cakes, make our own greek yoghurt, and try to have as few processed foods as possible.

Celia,

I use Greek yoghurt often but have always purchased it from the Greek market. Would you mind sharing your recipe so I may try to make it at home?

Dave, we use an Easiyo Yoghurt maker !

http://www.easiyousa.com/

Cheers, Celia

My impression is that Greek yogurt gets its special flavor from a mixture of sheep and cow's milk.

???

I googled "making vanilla extract" and found exactly what you are doing. But I found a suggestion that one might put in a touch of dark rum, or a bit of simple syrup (evidently most commercial vanilla extracts are sweetened). I think the dark rum sounds like a good idea...

Frank

You're probably right, Frank. We just use the term "greek yoghurt" to refer to thick creamy yoghurt that we can use in place of sour cream. That's what it's sold as here, and I doubt there's any sheeps milk in it.

Part of the reason I was trying to make my own vanilla extract is that the commercial ones have heaps of additives - the one we currently use has sugar as the main ingredient ! The dark rum does sound like a nice idea, but that means I'd have to buy another bottle..

And then, what in the world would a person do with a bottle of dark rum?

Oh wait, I have an idea...



At any rate -- I had a feeling you were using "Greek" in a different way. Like French fries. We have a Greek grocery store a few blocks from my house, and when we want that special flavor we go there for yogurt. But we are so lucky, we can also get wonderful rich yogurt at the local Indian groceries, and a completely different thick creamy yogurt at the Amish. Plus the stuff at the supermarket.

I wonder if you would enjoy Barbara Kingsolver's book, "Animal, Vegetable, Miracle"? She had a very similar concept to yours, living on a farm in Virginia (eastern US) she decided to become a "locavore" -- in other words, to produce as much of her family's food as possible, and never to buy food that came from thousands of miles away. Bananas became impossible, but they may have worked out some sort of rationalization for coffee.

Frank

Celia - 80 proof vodka contains 60% water. I would assume that should be enough.

Dave, we use an Easiyo Yoghurt maker !

http://www.easiyousa.com/

Cheers, Celia

Thanks for the link, *C*. I was just hoping you would not reply by saying something along the lines of..."Well, first Dave, you have to buy some sheep, then you have to feed them, then you have to get up at 4:00 AM to milk them, then..."

Aggghh! I wrote a longish response to you, Celia, which seems to have gotten lost in the tubes. To be brief, the ratio of water to ethanol will determine the overall polarity of the solvent. The more water, the more polar. And the solvent polarity will determine the degree of extraction of any given substance, so the relative ratios of extracted materials will change with changing solvent polarity.

Thanks for all your advice !

Frank, I'll have a look at the book on Amazon, thank you for the recco. I'm not really a locavore, I'll happily buy from anywhere in the world, but I am trying to "produce" as much of our food as I can. I say "produce", because obviously I'm not living on a farm, and I'm a lousy gardener, so I know I'm not really producing anything from first principles. But I'd like to get as far down the production ladder as I can...

I'm jumping in late to the discussion here, but have liitle to add to Stuart's analysis (amazing, since he's a physical chemist -- they usually can't boil water, let alone perform an extraction successfully ). A couple of thoughts: as Stuart said, the alcohol:water ratio determines the solvent polarity and, in turn, how well the extraction works. They might have you add water to vodka to increase the solvent polarity. Also, vanillin is fairly soluble in water (1g/100 ml) but other, minor components of vanilla extract such as piperonal are far less soluble in water, therefore requiring the use of alcohol in the extraction. For the same reasons, you need certain levels of alcohol in wine to extract color and tannins out of the skins, which is why Chaptalization (the addition of sugar to fermenting grape juice) was invented.

Mark Lipton

Thanks Mark. I'm trying some bottles with straight vodka, and some with vodka and a bit of water. I'll see if it makes a difference. It's nice to have some understanding of what's going on...

I wonder if you would enjoy Barbara Kingsolver's book, "Animal, Vegetable, Miracle"? She had a very similar concept to yours, living on a farm in Virginia (eastern US) she decided to become a "locavore" -- in other words, to produce as much of her family's food as possible, and never to buy food that came from thousands of miles away. Bananas became impossible, but they may have worked out some sort of rationalization for coffee.

Frank

I just had a nice moment - my 11 year old walked in and asked.."Mum, do people actually make frozen pies ? Do they really sell them at the supermarket ?

I'm not chopping up the beans, purely because that looks messy (how unscientific !).

Ok Wine Chemist checking in late to this party. Celia you might want to chop the beans up because I'm thinking that the more surface area you have exposed to the Vodka the better the extraction. There should be some sort of material like a nylon hose that you can put the chopped up beans in and tie closed. That should make getting the beans out when you are done an easy task.

Thanks Duane. I might try that next time - they're all set up this round...

Celia

From an article describing vanilla and synthesizing vanillin: "Vanilla extract is made by cutting the beans into small pieces and soaking in successive quantities of hot 65-70% alcohol."

Thanks Larry. Although I've read some articles to suggest that the heat affects the end aroma of the vanilla, and that macerating the beans cold gives a better result. Lots of people seem to agree about chopping the beans up though.

An update - it's been just over a week and the vodkas are colouring up very nicely...

Celia - you can also do this with a lot of other things besides vanilla. Fresh fruit soaked over time in vodka are called "Bounces". They are strained after a few weeks. Cherry and lemon peel, raspberries, cranberries, etc. Sweetened with sugar they can served on their own, but I'm sure they could also be used as extracts. I have some recipes in a book someplace and will try to post something more specific within a few days (between the ankle and getting my taxes done).

An update - it's been just over a week and the vodkas are colouring up very nicely...

And where are the photos, young lady? Are we just supposed to take your word for this?

young lady?

Young?

rwj