So, Do Coffee or Coffee Grounds Keep Mosquitoes Away?

It’s hard to imagine a more hated and more dangerous insect than the mosquito. Yes, I said dangerous.

That’s because mosquitoes are, in fact, one of the most lethal animals on Earth, as each and every year the diseases that hey spread kill millions and millions of people.

mixing crushed eggshell with coffee grounds
mixing crushed eggshell with coffee grounds

But even if you don’t fall victim to these diseases, they can still make you absolutely miserable whenever you’re outdoors.

So the obvious countermeasure is to douse yourself with bug spray, but if you are like me, then you’re increasingly worried about the chemicals in these sprays.

A better choice might be to go with something all-natural that will keep these bugs at bay. How about something like coffee, or coffee grounds? Will coffee keep mosquitoes away?

Yes, coffee can help to keep mosquitoes away by preventing mosquitoes from laying eggs in water sources where they reproduce. There’s also some evidence to suggest that the aroma of coffee can help mask human presence from mosquitoes.

Well, I guess you can chalk that up to just another one of coffee’s miraculous properties, aside from making the working world go round!

Coffee has legitimate utility in your mosquito prevention program, and I’ll tell you all about how to implement it down below.

It probably won’t be a total solution, but it’s definitely a good tool to add to your toolbox.

How Mosquitoes Find Their Prey

Before we learn how coffee can help keep mosquitoes away from us, it’s informative to learn how mosquitoes find us in the first place and where they come from.

For starters, female mosquitoes are the actual bloodsuckers, and they drink the blood of mammals- including people, obviously.


Mosquitoes are highly adapted and very successful at tracking down humans in all conditions, and they do this by homing in on a variety of indicators, namely exhaled carbon dioxide, body heat, movement and lactic acid excretion.

Also, bad news, they prefer type O blood. If you have that blood type, they can find you more easily…

All of this is made even worse if you’re outdoors by an elevated heart and metabolic rate.

If you are exercising or just hustling through the woods, you’re basically putting a spotlight on yourself for any mosquitoes in the vicinity.

So How Does Coffee Work to Keep Mosquitoes Away?

So we know now that mosquitoes home in at least partially by scent, specifically on the lactic acid coming through our skin and also the CO2 we exhale.

Coffee can directly help keep them from locating us because of its fragrance.

There just seems to be something about the aromatic compounds in coffee that can baffle and confuse mosquitoes.

A longer-term and even more effective solution that coffee can provide for us is as a preventative.

Sprinkling coffee grounds in any water source where mosquitoes might go to lay their eggs and reproduce means that less eggs will be laid and fewer of them will actually hatch. Sounds crazy, but it’s true!

Together, these two factors can give you a significant leg up on mosquito protection.

Coffee Grounds Can Prevent Mosquitoes from Laying Eggs in Water

If you want to prevent mosquitoes from using any water source as a breeding ground, all you need to do is dose it with some coffee grounds.

Unused coffee grounds are best for the task, probably because they have less of their vital compounds extracted from the brewing process.

Generally, the more coffee grounds you add, the less attractive the water source is to these insects in the first place, and also the more harmful it is to the eggs and young larva that might hatch.

Assuming it won’t hurt any other organisms in the pond, or if you just don’t care about it, put a big scoop of coffee grounds and old ponds and other containers where mosquitoes typically breed and give it a stir.

Burning Coffee Grounds May Prevent Mosquitoes from Smelling You

Coffee grounds also seem to show significant efficacy as a mosquito repellent, or rather as concealment, when the grounds are burned.

Mosquitoes already get a little disoriented by smoke in general, but burning coffee grounds seem to be especially effective at giving mosquitoes the slip.

Periodically adding coffee grounds to a fire, or even deliberately burning a small quantity of coffee grounds can be an effective repellent when you are outdoors.

Will Smearing Brewed Coffee On Your Skin Stop Mosquitoes from Biting You?

It’s uncertain. We know that the aroma of coffee seems to confuse mosquitoes by masking other human scents that they use to home in on us, but it doesn’t appear that coffee is an actual deterrent or otherwise harmful to mosquitoes.

I would say that if a mosquito were to land on you, even if you had coffee on your skin, they would still probably bite you because they have found the target, as it were.

On the other hand, coffee would certainly help to confuse or muffle your aroma somewhat, so it’s worth a try.

Some Folks Claim Moistened Grounds Can Also Confuse Mosquitoes

Some folks even go so far as to claim that moistened coffee grounds alone will emit enough fragrance to meaningfully distract and confuse mosquitoes, preventing them from finding you and biting you as easily.

This is definitely an anecdotal solution to the problem, but one that some folks swear by.

In any case, it’s worth a try in conjunction with other methods assuming you don’t have a fire handy to burn coffee, or are in any situation where burning it is out of the question or impossible.

How to Prepare Coffee as a Mosquito Repellent

If you’re going to use coffee as a mosquito repellent, the grounds are what you need. Preferably unused, fresh coffee grounds.

For disturbing mosquito breeding grounds, simply put a few generous scoops of coffee in the water where they are likely to breed.

I like to use at least half a cup for every gallon of water. Give it a stir, and the active compounds in the coffee will permeate the water.

As an area repellent, simply burn a quantity of fresh coffee grounds. Note that you can use the pre-ground stuff, and you’ll still get good results as long as it isn’t previously brewed.

Remember too that smoke itself is a mosquito deterrent, so using coffee in conjunction with a good, smoky fire will definitely give you some mosquito relief…

How Often Should You Use Coffee or Coffee Grounds to Repel Mosquitoes?

If using coffee grounds as a deterrent in water to prevent mosquitoes from breeding, I would add more coffee every 3 to 4 weeks. The compounds responsible are organic and will break down over time.

Inspect the water and if you notice any mosquitoes congregating on the surface or any little wrigglers in the water, it’s time to add more.

If you are burning coffee grounds to create area denial against mosquito attacks, simply keep an eye on the coffee grounds in or near the fire and add more as they burn away.

And once again, remember that smoke is your friend if you’re trying to keep mosquitoes at bay!

Is Coffee Safe to Use as Mosquito Repellent?

Yes. Burning coffee grounds are no significant fire hazard and they don’t produce any toxic fumes. Coffee isn’t even overtly toxic in water assuming there aren’t any fish or other creatures in the water that you care about.

And, if you wanted to try it, smearing coffee on your skin isn’t going to cause any harm if you aren’t allergic to it and the coffee isn’t piping hot, of course!

All in all, coffee is a highly safe tool in your mosquito prevention arsenal.

1 thought on “So, Do Coffee or Coffee Grounds Keep Mosquitoes Away?”

  1. I put used coffee grinds in pot planters which are located on porches to keep mosquitoes from congregating near doors. I discovered this years ago by accident, when I was trying to enrich the soil within the pot plants.


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