Grain Weevils Freezing Experiment

Took some grain weevils, froze for 24 hours, and proved to myself that they don't survive below freezing. I know, maybe a duh, but I wanted to know with some certainty. No idea if eggs survive the freeze.

Here's a before (bugs crawling all over the jar) and after (sleepy time for bugs). I watched the "after" jar for a full day; they have definitely moved on to the big grain bin in the sky. Click on pics if you need to see a closeup of dead bugs.

Before...

After...

Filthy weevils, that'll learn 'em!

Wow, that's disgusting! But glad you posted. I've been wondering the same thing. . .does it really kill em?

I cycle all my newly arrive grain though the freezer prior to storage. It's a big PITA (I don't have a chest freezer.) I'm glad to know the effort is worth while. Thanks passedpawn!

After losing a whole sack of 2-row to these little bastards, I am putting my grains outside on the back porch whenever the temperature is supposed to drop below freezing. Once spring starts, I'll probably nuke them with CO2.

I am not familiar with the biology of the grain weevil, but many kinds of beetles can survive a slow freeze. Up here in BC the mountain pine beetle can survive -40 C as long as they have a chance to burrow deep enough into the tree.

From what I read, you need to keep your grain at 0F for 4-7 days. That means your fridge/freezer combo is no good. You really can only use a chest if you want to be SURE.

The other option is obviously to brew more beer!

theredben said:

I am not familiar with the biology of the grain weevil, but many kinds of beetles can survive a slow freeze. Up here in BC the mountain pine beetle can survive -40 C as long as they have a chance to burrow deep enough into the tree.

From what I read, you need to keep your grain at 0F for 4-7 days. That means your fridge/freezer combo is no good. You really can only use a chest if you want to be SURE.

The other option is obviously to brew more beer!

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Hmmm, I guess my bugs didn't read that.

If they freeze, they will die.

love the weevil crawling around on my screen!

I seriously started to brush that bug off the screen. Then I simultaneously realized we're done with bugs for the winter here in Colorado, and remembered the subject of the thread.

Then I showed the page to my gf and told her I need to check my grains, and she started to brush at the screen.

Nicely done, and good info.

They can look dead and be revived. On the farm when we deliver grain to the elevator if they see any "dead" bugs they put them under a heat lamp to see if any wake up.

Freezing does kill grain beetles and their eggs. Almost all grains have the eggs on them but they won't hatch unless the conditions are right. Keep your grains in a cool, dry space and the eggs will usually stay dormant.

Hah, got you guys! Anyway, the experiment was real (even thought the little moving bug was not). I still have the jar with the "dead" ones, at room temp. If they revive, I'll know it. I don't see that happening, but I'll check for the next week.

Fun. So, you sent them to the great "protein rest" in the sky?

evil weevils, had a problem with them strait from the briess Bag....(1lb flaked barley)

jmferris said:

Fun. So, you sent them to the great "protein rest" in the sky?

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Their souls went there. The corporeal parts, mostly protein as you point out, went into my beer.

passedpawn said:

Their souls went there. The corporeal parts, mostly protein as you point out, went into my beer.

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Maybe a nice Metallica-inspired title? "Am I Weevil?", perhaps?

buffalobrewer said:

love the weevil crawling around on my screen!

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that was awesome. I tried to squash it. hahaha :cross:

Just a follow-up. I finally got around to freezing my entire grain inventory (I keep a lot). The weevils seem to ignore the dark grains, but the lightly kilned stuff like pils attract them.

I brewed with them several times, no biggie. Doesn't bother me even a little bit. But, you know, it's not the kind of thing you want your drinking buddies discovering.

So, I put the whole lot into the chest freezer for a day and a half. No more weevils.

Ugh. Do all grains really have weevils in them? I think my LHBS must take care of them as I didn't notice anything like that in my grains from them. They also have a high turnover rate so that might help.

When the Weevils wobble, do they fall down?

It does not hurt the grain to be defrosted again? Or do I need keep the grain in the freezer until I use them again?

hinke said:

It does not hurt the grain to be defrosted again? Or do I need keep the grain in the freezer until I use them again?

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They are fine after thawing. Back to room temp, they will keep for a long, long time.

Found a whole bag with them today...I wonder how I can "filter" them out from the grains when they are dead...

hinke said:

Found a whole bag with them today...I wonder how I can "filter" them out from the grains when they are dead...

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No need. Just close your mind and brew away. Believe me.

If you can suck the muscle off a pigs ribs, eat the unfermented eggs from fowl, slurp the tittie juice from a cow, suck the meat from a spider-like crab from the bottom of the ocean, enjoy the pig's muscles ground and stuffed into its own intestines....

I bought grains by weight for the 1st time from my LHB shop (usually was buying premade kits) and the flaked oats and wheat both had the suckers in them. The LHB didn't believe me until I picked up another bag of flaked wheat and they were crawling around in the bag.

The employee guy didn't seem to mind the bugs and said some people just brew anyway. Seriously? I pay money to buy things that I assume are not infested with bugs. He reluctantly traded out 2 bags, and guess what, one of the new bags had them too. Picked them out after pouring on a plate and sifting, then froze the bags. Won't be going back to them again. They must be storing them wrong, or got an infested bag and never noticed or cared if they did notice.

Getting them at your home is one thing...having an infested bag straight from the store is BAD.

spaceyaquarius said:

The employee guy didn't seem to mind the bugs and said some people just brew anyway. Seriously? I pay money to buy things that I assume are not infested with bugs. He reluctantly traded out 2 bags, and guess what, one of the new bags had them too. Picked them out after pouring on a plate and sifting, then froze the bags. Won't be going back to them again. They must be storing them wrong, or got an infested bag and never noticed or cared if they did notice.

Getting them at your home is one thing...having an infested bag straight from the store is BAD.

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While it is unpleasant to have insects crawling around in your raw ingredients, they are a part of what we do. The alternative would be for the maltsters to apply pesticides to their finished product, which none of us would want.

It probably has nothing to do with how the shop stored the grains since the eggs arrive in the grains themselves. Grain bags from many manufacturers are also notoriously poorly sealed - but unless it is a really bad infection, there's no way of knowing until you open the bag.

Of course, I would have happily exchanged the goods for weevil-free ones or given you a refund, but each homebrew shop handles these things differently. I would send the owner a friendly e-mail and share your concerns with them.

We have a big argon tank that we use to fill up the base grain bins, and we preemptively freeze many of the types of grain that tend to be more susceptible (e.g. flaked grains, smoked grains, Honey malt). I also check the bins multiple times each week, so we rarely see the critters. But a couple of times a year we do see them, and immediately go into containment mode.

You can also mix in some (food grade) Diatomaceous earth, after (or instead of) freezing the grain.

I've brewed with them more than I'd care to admit as it can be a little unsightly, BUT I haven't had a single issue yet and no one has come to me saying my beer taste "buggy". Think about it this way, what ever actually makes its way from the MLT to the pot is about to be boiled anyway. If you're still a little freaked out, add 2 whirlflock tabs at the end of the boil and what little protein bits from whatever managed to make it past the mash and boil (which is HIGHLY unlikely) will sink with the trub.

Recently received some flaked maize ablaze with weevils. Thought I'd bump my own thread. It is de regueur de jour, bumping old threads, n'est pas?

Since this was bumped just a few months ago…Yea I noticed weevils on the outside of a briess bag I bought. Cut it open and sure enough…not sure if I’m gonna try and brew it anyway or not. 50lb is a hell of a lot of waste.

Summa_Brewologica said:

Since this was bumped just a few months ago…Yea I noticed weevils on the outside of a briess bag I bought. Cut it open and sure enough…not sure if I’m gonna try and brew it anyway or not. 50lb is a hell of a lot of waste.

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sift them out before milling?

Summa_Brewologica said:

Since this was bumped just a few months ago…Yea I noticed weevils on the outside of a briess bag I bought. Cut it open and sure enough…not sure if I’m gonna try and brew it anyway or not. 50lb is a hell of a lot of waste.

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Ermagerd.

Brew with it. To quote Edward R Murrow, we are not descended from fearful men.

passedpawn said:

Ermagerd.

Brew with it. To quote Edward R Murrow, we are not descended from fearful men.

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I’m brewin it. I can’t drop $65+ dollars on another bag right now. But can’t brew until Saturday at the earliest. Hopefully they won’t multiply too much by then.

passedpawn said:

Ermagerd.
Brew with it. To quote Edward R Murrow, we are not descended from fearful men.

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You first!

Cheers! (I'm sorry, but I have standards to maintain, and they pretty much start with "No Meat!" in my beers )

day_trippr said:

You first!

Cheers! (I'm sorry, but I have standards to maintain, and they pretty much start with "No Meat!" in my beers )

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haha, I've definitely brewed with weevils. Yums!

They got into the flour in my kitchen. I was making pasta, and when sheeting it I could see them in the sheets. After cutting it into linguini, of course nobody noticed. Hakuna matata!