How to take a sample without letting in oxygen
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If you have a fancy conical fermenter with a side port, there's a way to run CO2 in and push a sample out. Same if you're fermenting in a corny keg. If you're using a bucket, I think the best you can do is avoid shaking when opening the lid, keep the beer as covered as possible as you take the sample, avoid splashing, and close it up as soon as you can. I have never "ruined" a batch doing that, or ever gotten judge comments in a competition that say my beer is oxidized. If you're really paranoid, I guess you could have a stream of CO2 running over the bucket opening as you're doing this, but I doubt it matters.
Using a bucket fermentor:
If you have CO2, you can flush the headspace to reduce the amount of air that has entered.
If you have a 2nd access hole in the lid, you can push the sample out with CO2, instead of sucking/siphoning. That way no air gets in.
- Sanitize airlock area
- Remove airlock
- Snake a sanitized 2' piece of thin hose (5/16" OD / 3/16" ID) through the airlock hole, a few inches below the beer level (not critical)
- Siphon 4-6 oz of beer out (suck method)
- Pull hose out of bucket quickly (so you don't get any flow back)
- Replace airlock
If you have CO2, you can flush the headspace to reduce the amount of air that has entered.
If you have a 2nd access hole in the lid, you can push the sample out with CO2, instead of sucking/siphoning. That way no air gets in.
Pushing out with CO2 or sampling port/spigot is ideal. Otherwise flushing headspace with CO2 when sampling/dry hopping gets the job done.
Any displacement you might have through the top will be replaced with 80% nitrogen anyways works for me. No matter how you remove fluid you need to replace that space, unless your under pressure. Co2 is also denser than air so pure co2 will push out the air if it's still fermenting.
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I was trying to find a way to do this with Speidel fermenters. I looked at the sample port on my Chornical and ordered these:
https://www.brewhardware.com/product_p/pcomp2.htm
https://www.ebay.com/itm/1-4-316-St...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
I drilled and mounted the first item mid way up ( about around the 3 gal area). I had to use a o-ring to make it water tight. Then mounted the valve. Works great with water, next beer I make will be true test
https://www.brewhardware.com/product_p/pcomp2.htm
https://www.ebay.com/itm/1-4-316-St...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
I drilled and mounted the first item mid way up ( about around the 3 gal area). I had to use a o-ring to make it water tight. Then mounted the valve. Works great with water, next beer I make will be true test
I don't ever test until I package. I just let the beer ferment three weeks, check final gravity, and keg that bad boy. If the gravity seems high, I warm the batch a bit first.
Been brewing along time and don’t test until I package. I don’t really buy into the 3 stable gravity reading school. It is a waste of beer and great opportunity to infect your batch. Most ales are fully attenuated in under a week and most certainly in 14 days. Also, FG is FG there isn’t much you are going to be able to do to change it. Although, I’ve never experienced a stuck fermentation either, but have had beers end higher than I would have liked, but taking gravity readings won’t change it.
Well, it depends... lol
You can just wait till it is done, 2,3,4 weeks, what ever you think it is.
But if you have plans for other than FG, you need to know where you are: Dry hopping, spundding, .... Some folks need more info.
You can just wait till it is done, 2,3,4 weeks, what ever you think it is.
But if you have plans for other than FG, you need to know where you are: Dry hopping, spundding, .... Some folks need more info.
2,3,4 weeks? FFS an ale is done in a couple days usually.
Fermenting in corny kegs makes sampling easy. Just attach short cobra tap, apply few lbs of pressure, and done.
Made an 1.065 IPA a few weeks ago. It was under 1.010 in less than 4 days, naturally carbonated and had been chilled for several days already when put on tap on day 9. Amazing fresh beer.
3 weeks???
Fermenting in corny kegs makes sampling easy. Just attach short cobra tap, apply few lbs of pressure, and done.
Made an 1.065 IPA a few weeks ago. It was under 1.010 in less than 4 days, naturally carbonated and had been chilled for several days already when put on tap on day 9. Amazing fresh beer.
3 weeks???
andrewmaixner
Well-Known Member
Beyond that, you can get 10, 13, 20 inch blunt stainless syringe needles, attach to a 30ml syringe, and pull the sample with that also. I just ordered some for checking pH on my sours.
Can also flush with CO2 as mentioned, if one really is concerned.
Well, guess it depends on what you are making, Barlywine, stout, triple, ... if all you make is IPA... for some of us, young hoppy beers are.... well, young! I have beers that are 3 months in and still "green"
If you’re worried about oxygen ingress, one of the worst things you can do is an extended primary. Not everyone is worried. The OP is.
Something that hasn't been mentioned yet is an "in the fermenter" SG measuring device. I use a Tilt hydrometer. I don't trust it for accurate SG measurements, but it lets you know the progress of fermentation reliably, and especially when fermentation has ended (SG graph "flat lines".) With this type of monitoring, you don't have to open the fermenter, or even sample.
Depending on time to assume FG has been reached can be unreliable. Most of my moderate gravity ales are at FG in about 4 days. However, I just finished an Imperial Belgian Tripel that took 20 days to reach FG.
Depending on time to assume FG has been reached can be unreliable. Most of my moderate gravity ales are at FG in about 4 days. However, I just finished an Imperial Belgian Tripel that took 20 days to reach FG.
In that light, a refractometer only requires 1-2 drops. Using a correction calculator you can determine your current gravity within a few points precise with minimal intrusion and air (O2) ingress. If the gravity isn't dropping after 2-3 days it's probably done.
I often add my sugar syrups (a bit thinned down) when fermentation has subsided some (say 50-70% from OG) with an adapted funnel that reaches underneath the beer level. Just keep the funnel full while pouring to prevent sucking in air.
I have a few bucket lids I drilled a 1" hole in (stoppered with a regular bung). I add dry hops through that while flowing a low stream of CO2 through the airlock port. I really prefer that method over lifting the lid. It only takes about a minute, and air ingress is minimal or zero.
Using that lid, I can also easily siphon or even push finished beer into my 100% liquid pre-purged keg with minimal O2 exposure.
whiskeyjack
Well-Known Member
If bottling it is pretty crucial to check fg. I keg and forget to check it half the time. After a while you know how your beers behave. Most of my ales krauzen drops in 2-4 days, once i see this i give it another 5-10 days, crash it then keg it. If i bottled i would be hesitant to do what i do as far as checking before packaging. Only thing I can say regarding op question is just try to be quik and efficient when taking a sample. Have everything you need near you and sanitized, open up grab a sample close asap. Large turkey baster is faster then syphoning imo, if you can use it. If you are bottling most of the O2 exposure will come from bottling. Just limit the amount of times you open up. I know when I first started I was always peaking in the bucket to have a look. Don't do that 
I always take the sample and close the lid quickly but still wonder how important it is. The bucket isn't an oxygen barrier, and the water (Star San) in the airlock isn't. I feel that oxygen ingress is greatly limited by these barriers, but don't really know how much.
I sample with a method similar to Islandlizard, but instead of the 'suck method' , I use a 30cc syringe attached to the tubing to withdraw the sample. I will admit I'm much less worried about taking multiple samples than I used to be. Now I take one when I think it's finished and another when I'm ready to bottle.
For a hydrometer sample won't you need at least 4-6 oz of beer? Do you pull 4-6 times or use a refractometer? I know they make 100ml syringes, possibly larger ones.
Yeah, I've tried the 60cc ones( biggest one I had) but it was kind of unwieldy. I usually withdraw 2.5 syringes full- so I guess it's around 75cc. The rubber plunger also only lasts about a dozen batches because the starsan eventually eats it. I saw somewhere on this thread someone talking about a stainless steel syringe. Maybe I should look for one of those.
Yea I'm one of those guys in no rush. I wait 3-4 weeks take the FG reading when I bottle. Yea I use buckets and don't waste time stairing at a glass carboy watching my brew ferment.
I like the idea of using a syringe, although a good suck and siphon works equally well! I keep a 2' piece in the bottom of a Starsan bucket perpetually.
The rubber plunger and/or the side walls of the syringe are lubricated. That lubrication either wears off, or gets "eaten" as you said by the liquids. I've been filling inkjet cartridges with syringes and the ink or cleaners dissolve the lubrication over time too. Lubricating the plunger with a little bit of "plumbers grease," the 1/2 oz little tubes or vats with silicone grease used for lubricating faucet cartridges, keeps them going. A $5 tube or vat from the hardware/plumbing store lasts a long time. They do come in larger sizes, but are harder to find.
Agreed, for most beers time is less critical, but at times you want or need to keep an eye on progress of attenuation, say to dry hop (NE)IPAs, add sugar syrups to Belgians after 50% or so has fermented, or raise the temps for a Diacetyl rest at the right time. And we sure would hate to find out after 4 weeks that that Saison has stalled at 1.012. If using larger samples is a problem, a refractometer can keep track of progress a drop at a time, and if one keeps the data in a table or spreadsheet you can monitor that progress rather closely. There's also something about that taste sample halfway... You also learn something.
Each to his own as far as taste goes. I'd never make a Belgian anything. Haven't tasted one I like yet. I've had a few imports given to me as gifts and after one sip I poured them down the drain. I don't like fruit in my beer either. A friend had what I think was an Apricot Wheat. UGG. On sip as enough to say No Thanks. But then that's just little old me.
Mothman
Well-Known Member
I use a turkey baster through the air lock port in my bucket lid.
Doesn't prevent oxygen exposure but I'm confident it helps minimize it enough to not concern me.
And I bottle, so I know the minimal oxygen exposure during a couple fg samples is nothing compared to what occurs when I bottle (which I try to minimize as well, and again doesn't really cause me any concern).
Doesn't prevent oxygen exposure but I'm confident it helps minimize it enough to not concern me.
And I bottle, so I know the minimal oxygen exposure during a couple fg samples is nothing compared to what occurs when I bottle (which I try to minimize as well, and again doesn't really cause me any concern).
