Wine Thief - Testing FG - Add Test Sample Back?

I purchased a wine thief planning to see if my first batch is finished fermenting and reached FG before bottling (as apposed to using a calendar).

Is it ok to dump the sample back into the batch like the "instructions" say?

Jiffster said:

I purchased a wine thief planning to see if my first batch is finished fermenting and reached FG before bottling (as apposed to using a calendar).

Is it ok to dump the sample back into the batch like the "instructions" say?

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In a wine thief, yes. As long as it was properly sanitized first of course. You don't really "dump" the sample back in- you push against the side of the carboy so it gently goes back into the wine, so it avoids oxygenation and splashing. Or, you can take the sample and put it in a glass after the reading, and drink it. Either way!

Although you can return the sample safely, if your sanitation methods are impeccable, there are some risks involved such as infection and oxidation. Each time you stick that (fat) thief in there you disturb the headspace, losing more CO2 replacing it with air. This is relatively more of an issue the smaller the batch. For small batches, such as a gallon or less, use a refractometer (and online calculator) instead, since they only need one drop.

I would also caution against dropping a hydrometer into a wine thief. I broke my first hydrometer doing that as it plummeted to the bottom like a torpedo, where it struck and disintegrated. Don't do that!

Only take samples when absolutely needed, and if you use buckets, don't remove the lid until ready to rack. You can siphon samples with skinny 1/4" OD tubing (hose).

Thanks folks. This is a 5 gallon batch currently fermenting in a carboy.

Can I attach a 1/4" tube to an auto siphon or do I need to use something else?

I never return the sample from my wine thief. Fear of contamination, its a risk that I find can be avoided. The amount of beer that goes into the hydrometer jar is not very much and I like to drink the test beer to get an idea of how things are going.

You can repitch the samples taken from your preboil though

cannman said:

You can repitch the samples taken from your preboil though

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Preboil samples? Excuse my ignorance, please, I'm not sure what that is.

Jiffster said:

Preboil samples? Excuse my ignorance, please, I'm not sure what that is.

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It's a sample of wort taken after the mash is completed and all the runnings are evenly mixed.

This gravity reading coupled with the preboil volume will give the brewer his/her mash efficiency.

This is a useful piece of information. Find out more about it here if you're interested.

Jiffster said:

Thanks folks. This is a 5 gallon batch currently fermenting in a carboy.

Can I attach a 1/4" tube to an auto siphon or do I need to use something else?

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No auto siphon needed for this.

For a 5 gallon batch in a carboy, it's not that bad to use a thief, but in buckets it's impossible without lifting the lid, a big no-no.

Remove the airlock (and bung), and snake a 2-3' long piece of sanitized 1/4" OD tubing under the beer surface. Then give it a suck and siphon into a glass or plastic cup. When enough, pull it out of the carboy, so it doesn't flow back. You could use a syringe or turkey baster instead, to create the suck. Practice with a bucket of water first to get the hang of it.

cannman said:

I never return the sample from my wine thief. Fear of contamination, its a risk that I find can be avoided. The amount of beer that goes into the hydrometer jar is not very much and I like to drink the test beer to get an idea of how things are going.

You can repitch the samples taken from your preboil though

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agreed. I sanitize the crap out of my wine thief but the hydrometer jar is another story. Ive never considered adding the sample back into the fermentor. Maybe you should get a smaller hydrometer jar so you arent wasting as much volume to test it? I just use the dingy plastic tube it came in when I bought it

Thanks folks!

I drink it, its a good way to sample the taste

Jiffster said:

Preboil samples? Excuse my ignorance, please, I'm not sure what that is.

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At all grain, once you are done extracting the sugars and before you boil the wort, you take a gravity reading, ie preboil.