Thursday, December 18, 2008

Rosemary Infused Olive Oil: Another Easy Edible Holiday Gift

I think I'm finally finished now with my homemade edible holiday gifts. My last project was to take some of the rosemary I had clipped and had leftover from making the rubs and turn it into something else. I found these very pretty little glass bottles with spouts at CostPlus. Surely, I could do something with them.

Of course, the answer was to make an infused olive oil but my concern was botulism. I certainly don't want to make anyone sick.

I did some research and found all sorts of techniques for infusion. I have to say up front that I'm researching a story for the San Diego Union-Tribune's food section on olive oils and one of the most fascinating tidbits I've discovered is the powerful flavor and aroma that comes when, in fact, the olives are pressed with the flavor additive -- whether it's lemons or blood oranges or garlic. The essential oils of the other ingredient come through in a very robust, very distinctive way. And, it maintains the integrity of the oil. You just don't get the same complexity in an infused oil.

However, most of us don't press our own olive oil and if we want to make flavored oils we have to come up with alternatives. I learned that one of the worst things you can do is introduce water into the equation. It's not the olive oil that is the problem, according to The Olive Oil Source. It's water -- in the form of fresh garlic, lemon peel, herbs, fresh peppers or spices -- that supports bacterial growth. Additionally, there's the risk of using fresh foodstuff that's been in the ground. It's another botulism hazard. That would include fresh garlic.

So, how do you get around this? Well, you can just go ahead and mix all these ingredients, keep the oil refrigerated and use it within a week. You can preserve the ingredients you're going to add. You can press the olives and the ingredients together (as noted above), perhaps roasting the garlic before pressing. Or you can dry the herbs, etc. to eliminate the water.

I poked around some more and discovered an interesting recipe for rosemary olive oil from Whole Foods that seemed to fit my new requirements. Almost. It calls for granulated garlic, which I couldn't find and didn't have time to canvas different markets for. Instead I found dehydrated sliced garlic, which I think I actually prefer. Aesthetically, it just looks cool. And having tasted a slice, I can tell you that it delivers on flavor and strength. And, it should have no moisture content.

That fit the bill for eliminating water and bacteria. So did the dry peppercorns. And, I left the rosemary out to dry for several days.

The other part of this recipe that I liked in terms of safety--perhaps without reason--is that it calls for the oil to be heated to 150 degrees. In my mind it's just another preventive measure, but perhaps it's unnecessary and only useful for the infusion of the herbs and spices. Then again, heating the oil breaks it down. But I decided to go ahead and try it.

So, here's what you do. I've linked to the exact recipe above from Whole Foods but precision isn't necessary here in terms of measurements, especially if, like me, the bottles you found aren't the same size as what they list.

Thoroughly wash the bottles, using hot soapy water. Rinse them well and let them dry completely. Again, make sure there's no moisture left inside.

In a large saucepan, empty a bottle of good extra virgin olive oil and heat the oil to 150 degrees (a candy thermometer works well for this). In my case, I got lucky. A liter bottle ended up filling the four bottles I had.

While the oil is heating, fill the bottles with your herbs and spices. I placed a couple of sprigs of rosemary inside, along with a dozen or so peppercorns and half a dozen slices of dehydrated sliced garlic. You could use any dried herbs, peppers or spices in the combination you like.

When the oil is ready, ladle it into a funnel to transfer the oil into the bottle opening, leaving about an inch at the top. I can tell you from trial and error that unless your saucepan has a spout of some kind, the ladle is your best bet. Don't do what I did at first and try pouring it directly into the funnel. You'll end up with a hot, oily mess.

Seal the bottle. The Whole Foods recipe says to shake it to mix it but a) I think that's because of the granulated garlic they call for; it's not really necessary with sliced garlic and b) I'm using pour spouts and shaking wouldn't be a good idea. But use your judgment here. In any case, the recipe says to store the oil in a cool, dark spot for a week to let the flavors meld before using.

One additional benefit of using this recipe is that there's a link on the Whole Foods recipe page that leads to a PDF with printable gift tags that include a serving suggestion. So, I got a clever set of tags to accompany my gifts.

Now, to be on the safe side, I'm still going to recommend to my recipients that this go into the refrigerator and be used fairly soon. But I'm less nervous about it than I would have been otherwise.

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  1. Looks GREAT, Caron! I'd never seen that sliced garlic before and I thought I'd looked at every spice section in town! Ha!

    Thanks for the tutorial!

  2. what lovely bottles of oil! Happy Holidays Caron!

  3. Glad you're doing olive oil infusion the safe way, by using dried herbs.

    You can use fresh herbs in your gifts, but you should tell people to use within a month or so. When the oil starts to get cloudy, that indicates bacterial growth.

  4. If you use a slow cooker on high for 1 1/2 hours, you get a wonderfully infused olive oil and can strain out the rosemary. When stored in a clean container, it lasts a long time.