Question about salad dressings

[Carrie L.]

How long do you keep homemade salad dressings with fresh garlic or shallots in them? Does the vinegar (and/or oil) preserve them, or do they build up bacteria relatively quickly?
I tend to keep mine for a few weeks, but wondering if that is too long...

[Karen/NoCA]

I do the same thing Carrie, usually keep leftover vinaigrette a week to ten days in the refer. I've read something about garlic being a problem, but never have had one myself. I would suspect the vinegar takes care of that. However, I am sure one of the science guys will chime with a better explanation.

[Jenise]

I'm not a science guy but I have a sensitive nose and palate, and have never noted an issue, Carrie, with dressings based on oil, vinegar, garlic and salt. Other fresh ingredients can introduce things with a shorter shelf life, but think about the fact that oil in itself is something of a preservative--keeping an oil film on top of newly opened jars of anchovies, sun dried tomatoes and a number of other things of that type preserves those items where if exposed, they grow mold.

[Carrie L.]

I'm not a science guy but I have a sensitive nose and palate, and have never noted an issue, Carrie, with dressings based on oil, vinegar, garlic and salt. Other fresh ingredients can introduce things with a shorter shelf life, but think about the fact that oil in itself is something of a preservative--keeping an oil film on top of newly opened jars of anchovies, sun dried tomatoes and a number of other things of that type preserves those items where if exposed, they grow mold.

So you think it's safe to keep them longer? A few months maybe? (I will not hold you responsible for any potential, future illness based on your response.)

[GeoCWeyer]

I think it is safe because of the acid of the dressing. I always try to add all my dry and fresh ingredients including the salt to the acid, stirring the blend until the solid ingredients are covered and have had a chance to soak up some of the acid. Then I add the oil. IMHO this mixture can be kept for quite a while in the frig.

[Jenise]

Yeah, if there were fresh fruits or cheeses in there, I'd worry a little more about shelf life, but I make dressings that often sit in the fridge for 2-3 months and have NEVER had any problems.

[Paul Winalski]

The problem with garlic would be botulism. You're safe with salad dressing because Clostridium botulinum can't grow in the presence of either oxygen or an acidic environment, and the vinegar provides both. What's dangerous is to keep garlic cloves in vegetable oil. The oil completely seals out oxygen from the air, providing just the environment that the bacteria need. EVOO might have sufficient acidity to guard against the bacteria growing, but I personally wouldn't risk it--the downside if you get it wrong is really horrible.

-Paul W.

[Jo Ann Henderson]

Interesting that you would state that about garlic, Paul. I roast garlic and keep preserved in a jar of EVOO with a bit of cracked black pepper (sometimes salt and/or herbs) all the times. Often for months, replinishing and using off it as needed. Never had any gastrointestinal problems. Now you will have me worried!

[Christina Georgina]

Heat in the roasting process should inactivate the clostridium spores. Raw garlic preserved in oil would be a problem.

[GeoCWeyer]

The old fashioned oven/oil canning method was done for years by many with no negative results. It was also done by the few with deadly results.

[Paul Winalski]

Unfortunately the roasting process might NOT kill the Clostridium spores--they're extremely hardy. But the acidity of EVOO may be sufficient to kill the bacteria from any spores that activate. There have been cases of botulism from roasted garlic cloves stored in oil. It's rare (as is botulism in general), but it has happened.

-Paul W.

[David Creighton]

for me, garlic vinagrettes seem to take on a rancid like character fairly quickly - don't know why.

[Jenise]

David, I agree with you. Growing up, my family ate salad with every dinner and it was my job to make it. I was trained by my mother to make our standard everyday dressing in a big jar, just garlic+oil+vinegar that we would then use up over the next month-ish, and it definitely changed from first to last. I always thought of it as a tinny flavor. Still love the combination, but I make it fresh in the bottom of the bowl each time we want that salad.

[Mark Lipton]

David, I agree with you. Growing up, my family ate salad with every dinner and it was my job to make it. I was trained by my mother to make our standard everyday dressing in a big jar, just garlic+oil+vinegar that we would then use up over the next month-ish, and it definitely changed from first to last. I always thought of it as a tinny flavor. Still love the combination, but I make it fresh in the bottom of the bowl each time we want that salad.

Jenise,
My job was to make the salad dressing, too (as well as the coffee for my father and setting the table). Unlike you, I made it fresh every night: oil, vinegar, salt, pepper, dry mustard, garlic and dried tarragon. I'd make it in a small jar and dress the salad when it was on the table. I wasn't clever or creative enough to try storing it, I guess.

Mark Lipton

[Dale Williams]

My job was to make the salad dressing, too (as well as the coffee for my father and setting the table). Unlike you, I made it fresh every night: oil, vinegar, salt, pepper, dry mustard, garlic and dried tarragon. I'd make it in a small jar

Voila, the birth of a chemist! No chemistry set with test tubes required.

[Mark Lipton]

My job was to make the salad dressing, too (as well as the coffee for my father and setting the table). Unlike you, I made it fresh every night: oil, vinegar, salt, pepper, dry mustard, garlic and dried tarragon. I'd make it in a small jar

Voila, the birth of a chemist! No chemistry set with test tubes required.

No doubt that helped, Dale, but the chemistry set in the basement also did its job.

Mark Lipton