Low FG of 1.000 for My First Two Batches

[BeeSpojj]

Hello all,

I have now completed two all-grain batches, the first bottled, the second ready for bottling. But I have a potential issue. Both batches have finished at a stable FG of 1.000. My hydrometer is calibrated at 1.004 at 68F in water, and both my beers have finished at 1.004 (hence 1.000). FG readings have been taken from the top of the fermenter into a cylinder and measured at 68F.

Here were my grain bills (aiming for 2.5 gallon batches):

Recipe 1:
-3.3lbs Bohemian pilsner
-1.11lbs pale Canadian 2 row
-0.75lbs honey malt
OG = 1.030

*note: the mash temp for this first attempt was very low, so the beer has next to no body. Good ol rocket fuel.

Recipe 2:
-3.5lbs German Pilsner
-1.15 Canadian 2 row
-0.6lbs honey malt
-OG = 1.030
-added DME due to having a very low OG.
Actual OG = 1.048

*note: mash temp was held at 148F, so the beer has a nice light body to it. Much better than the first.

Both batches started with an OG of 1.030 (second batch was fixed) which was way off target, but I got the answer that this was due to using and having way too much water going into my boil in another thread (thank you). The yeast that was used for both batches was Safale US-05 and the yeast was re-hydrated before pitching. Fermentation went very well for both batches and samples were taken when the airlock had one bubble about every 2+ minutes (Total fermenting time of 2 weeks at 65F to be safe) and taken 3 days later to confirm stability.

Both beers have turned out very well in my opinion, both are very clear, and have great flavor and aroma.

My first thought for both beers was infection. However, all equipment was sanitized very thoroughly and carefully and both batches were added to the fermenter carefully to avoid contamination. Secondly, both beers do not taste sour at all, they both taste like a very nice dry, crisp beer for lack of a better explanation. Finally, there was no sign of infection in the fermenter itself. The beer looked clear and there were no bacterial films on top of the beer or on the sides on the fermenter.

Am I just getting lucky with having this low of a FG? Is it because I am mashing at a low temperature so I have a more fermentable wort? BeerSmith had a predicted FG of 1.010, so I'm not sure why I ended so low.

Any suggestions/comments would be greatly appreciated.

Cheers,
Brandon

 

[RPh_Guy]

Any chance you could post a photo of the hydrometer reading?
It's either contamination or some kind of issue reading the hydrometer.

 

[jdauria]

What temp is the beer when you take FG readings? If cooler or warmer than what the hydrometer is calibrated, 68F in your case, you need to us calculator available online to adjust your gravity based on temp. Also where you are using dry yeast, are you pitching a full pack? If so, one 11 gram pack for a 1.030 2.5 gallon batch is double the yeast you need, which could be why your finishing so low. Also mashing at 148F will lead to a drier (lower FG) beer as it sacrifices sugars for yeast food. So combination of low mash temp and overpitching yeast could be your main reason.

Also what are you using for a thermometer? Did you calibrate it? Boil some water and make sure it reads 212F or if you are above sea level, whatever temp water boils where you are. Then add some crushed ice to cold water and see if it reads 32F. If you are using a cheap thermometer, you could be off on mash temp and mashing even lower than 148F.

 

[RPh_Guy]

He said he's measuring FG at 68°F.

I'm not so sure overpitching and low mash temp would cause 100% apparent attenuation... Especially since the second recipe contains DME which generally isn't super fermentable.

 

[Amadeo38]

Did any of your previous batches prior to going to all grain use lallemand Belle Saison yeast? I would wonder if you have a diastaticus infection in your carboy? If not that yeast specifically, check the other yeasts you’ve used in your extract batches to see if they have a dia+ indicator. Otherwise, I would assume it’s some combination of low OG, low mash temp, and slightly incorrect hydrometer reading. Did you calibrate in distilled or RO water?

 

[Steveruch]

He said he's measuring FG at 68°F.

I'm not so sure overpitching and low mash temp would cause 100% apparent attenuation... Especially since the second recipe contains DME which generally isn't super fermentable.

I routinely get 80% attenuation with Briess pilsen dme.

 

[RPh_Guy]

Unless I'm mistaken, 80% is not 100%.

 

[Steveruch]

Unless I'm mistaken, 80% is not 100%.

It isnt. I was responding to the claim of dme not being super fermentable. I'm not sure where super fermentable boundary is, but 80% can't be too far off .

 

[bracconiere]

Unless I'm mistaken, 80% is not 100%.

lol, while we're being picky wouldn't 100% be less then 1.000, like 0.996 or something?

 

[RPh_Guy]

lol, while we're being picky wouldn't 100% be less then 1.000, like 0.996 or something?

We're talking about apparent attenuation, not actual attenuation.

100% apparent attenuation.

 

[BeeSpojj]

View attachment 675578 View attachment 675579

Any chance you could post a photo of the hydrometer reading?
It's either contamination or some kind of issue reading the hydrometer

Here is a picture of both the hydrometer reading of a sample I just took and a picture of the fermenter (no infection apparent). The hydrometer actually reads 1.008 which goes to 1.004 after calibration correction which still seems low but not as bad as 1.000 that I thought it was. Hydrometer instructions say to read at the top of the meniscus so I know I am reading it correctly. View attachment 675577 View attachment 675577 View attachment 675578 View attachment 675579

What temp is the beer when you take FG readings? If cooler or warmer than what the hydrometer is calibrated, 68F in your case, you need to us calculator available online to adjust your gravity based on temp. Also where you are using dry yeast, are you pitching a full pack? If so, one 11 gram pack for a 1.030 2.5 gallon batch is double the yeast you need, which could be why your finishing so low. Also mashing at 148F will lead to a drier (lower FG) beer as it sacrifices sugars for yeast food. So combination of low mash temp and overpitching yeast could be your main reason.

FG readings are being taken at 68F which is what my hydrometer is calibrated for. I pitched 70% (8 grams) of an 11.5g US-05 dry yeast pack (rehydrated before pitching). I'm using a MasterChef thermometer and it is calibrated and works fine.

Did any of your previous batches prior to going to all grain use lallemand Belle Saison yeast? I would wonder if you have a diastaticus infection in your carboy? If not that yeast specifically, check the other yeasts you’ve used in your extract batches to see if they have a dia+ indicator. Otherwise, I would assume it’s some combination of low OG, low mash temp, and slightly incorrect hydrometer reading. Did you calibrate in distilled or RO water?

Only have made the two batches so far, both with US-05 dry yeast.

 

[RPh_Guy]

It might be worth checking the hydrometer reading again in some 68°F water given that there are some... discrepancies.

Also, the absence of a film does not mean that a beer isn't contaminated. Wild microbes do not always cause a pellicle.

 

[BeeSpojj]

It might be worth checking the hydrometer reading again in some 68°F water given that there are some... discrepancies.

Also, the absence of a film does not mean that a beer isn't contaminated. Wild microbes do not always cause a pellicle.

That is true but bacteria is often visible, however I'm starting to think it might be a wild yeast contamination. Maybe it had something to do with when I was rehydrating the yeast. Process was boiling water, for sterilization, letting it cool to the proper temp, adding the yeast, letting it sit for 5 mins, stirring, letting it sit for 5 more mins and pitching. Pot was sterilized prior to boiling.

 

[jdauria]

View attachment 675585 View attachment 675586 View attachment 675587 View attachment 675578 View attachment 675579 Here is a picture of both the hydrometer reading of a sample I just took and a picture of the fermenter (no infection apparent). The hydrometer actually reads 1.008 which goes to 1.004 after calibration correction which still seems low but not as bad as 1.000 that I thought it was. Hydrometer instructions say to read at the top of the meniscus so I know I am reading it correctly. View attachment 675577 View attachment 675577 View attachment 675578 View attachment 675579

Only have made the two batches so far, both with US-05 dry yeast.

You are suppose to read the hydrometer at the bottom of the bubble of wort that attaches to the hydrometer, not the top. See this...https://www.lovebrewing.co.uk/guides/wine-making/how-to-use-a-hydrometer So it looks like 1.012 or 1.013 in your first pic. Second pic is too small too tell.

Also as you can see in your first picture, there are a lot of bubbles sticking to the hydrometer. Since there is carbonation in the beer from fermentation, you want to try to drive the CO2 out of solution as the rising gas could give you a false reading. What I do is pour the wort sample back and forth between two glasses 10-15 times. The splashing will release all the CO2 and you will get a head of CO2 bubbles in the glass. Let it sit for a few minutes and then pour back into the hydrometer tube and take a reading.

 

[RPh_Guy]

You are suppose to read the hydrometer at the bottom of the bubble of wort that attaches to the hydrometer, not the top.

Some hydrometers are calibrated to be read at the top of the meniscus, and he indicated that the one he's using is one of them.

So it looks like 1.012 or 1.013 in your first pic.

??? I don't think so. The thick line is 1.000

Looks right around 1.007-1.008 to me.

Also as you can see in your first picture, there are a lot of bubbles sticking to the hydrometer. Since there is carbonation in the beer from fermentation, you want to try to drive the CO2 out of solution as the rising gas could give you a false reading. What I do is pour the wort sample back and forth between two glasses 10-15 times. The splashing will release all the CO2 and you will get a head of CO2 bubbles in the glass. Let it sit for a few minutes and then pour back into the hydrometer tube and take a reading.

This is great advice, but bubbles would make the reading appear higher, not lower, so this obviously can't be the cause of the unexpectedly low reading.

 

[jdauria]

Some hydrometers are calibrated to be read at the top of the meniscus, and he indicated that the one he's using is one of them.

??? I don't think so. The thick line is 1.000
View attachment 675619

Looks right around 1.007-1.008 to me.

This is great advice, but bubbles would make the reading appear higher, not lower, so this obviously can't be the cause of the unexpectedly low reading.

Ah, never knew that about some being calibrated to read at the top. That makes me want to double check mine, though I usually use a refractometer anyway.

Bubbles would read higher, doh...right...me and gravity don't get along. ;-)

 

[Day-Day]

I'd call that 1.008 and check your hydrometer with distilled water and see if it reads 1.000, also look on the hydrometer and see what temp it's calibrated to. All my hydrometers say calibrated at 60 degrees F. When I put 60 degree F distilled water in them, they read 1.000.

Does your hydrometer say 68 degrees, or is that just the temp you are checking it at?

 

[BeeSpojj]

I'd call that 1.008 and check your hydrometer with distilled water and see if it reads 1.000, also look on the hydrometer and see what temp it's calibrated to. All my hydrometers say calibrated at 60 degrees F. When I put 60 degree F distilled water in them, they read 1.000.

Does your hydrometer say 68 degrees, or is that just the temp you are checking it at?

Calibration temp is definitely 68F as you can see in the hydrometer directions. In 68F water it still reads 1.004, making all my FG readings 4 points less than what they appear. View attachment 675796 View attachment 675797

 

[Day-Day]

View attachment 675798 View attachment 675799
Calibration temp is definitely 68F as you can see in the hydrometer directions. In 68F water it still reads 1.004, making all my FG readings 4 points less than what they appear. View attachment 675796 View attachment 675797

Okay, thanks for clearing that up.

Two questions:

1) Are you checking that hydrometer with distilled/RO water, that could possibly effect the reading.
2) Have you calibrated the thermometer that you mash with? If it's off you could be mashing much lower than expected, possibly contributing to the low FG.

I have two nice digital thermometers that I calibrate regularly and cross check all my temp readings with both thermometers during brew day to try and rule out these type of issues.

 

[RPh_Guy]

that could possibly effect the reading.

Tap water will not significantly affect a gravity reading. Even very high minerality like 500ppm TDS would only increase the s.g. by about 0.00027.

Great advice with the thermometers, but a low mash temp alone wouldn't cause 100% attenuation.

 

[BeeSpojj]

Hello all,

So I took another reading today to see if anything had changed and it seems as though something did. The hydrometer read 1.006, therefore having a FG of 1.002. Again, the reading was taken at 68F, the beer is still crystal clear and there are no signs of infection in the beer or in the fermenter. So we are definitely still at a low gravity reading. I retested my thermometer alongside a non-digital thermometer and they both read the same temps, indicating that my thermometer was definitely accurate during mashing (which was held at 148).

So back to the question, is this then a possible wild yeast infection, a possibly bad hydrometer, or just luck with the yeast attenuation? For my next batch is it worth trying to sprinkle the yeast directly into the fermenter without re hydrating it?

For all I know it might not be a bad thing at all, it just makes me nervous after always reading/seeing brewers hit the proper final gravities of say 1.008-1.012 when making ales.

 

[Day-Day]

To be honest, there's no way we can answer your questions with any degree of certainty. Could it be a wild yeast infection? Possibly. Could it be a bad hydrometer? You already know it's not calibrated properly, so I'd just get a new one. Is it just very high attenuation? Again, possibly.

A couple things to note here.

1) Miscalibration is not always linear...I've seen thermometers that read 3 degrees off at one temp, and 10-12 degrees off at a much higher or lower temp. I've seen scales that do the same thing. Just because your hydrometer is off to a certain degree when the wort is at one concentration, doesn't necessarily mean it's going to be off to the exact same degree at another concentration. You know it's not calibrated properly...I'd just get rid of it.

2) When you calibrate a thermometer, you check it against either iced water or boiling water, because they will be 32/212 degrees F. repsectively. There's no way to tell if that non-digital thermometer that you checked it against was properly calibrated. Not saying it wasn't, but there's only one way to find out.

3) You seem to be looking for the one "Thing" that is driving down your FG. That's not always the case. Could it be one definitive thing, sure. It could also be a number of factors working together that are creating this issue. This is why it's important to double, then triple check everything in your process. For example, you mentioned you fermented at 65 degrees F, was that ambient temp or actual wort temp? A high fermentation temp can increase attenuation. All these little things add up.

No one here is going to be able to look at a few pictures of a hydrometer sample and say for certain that it's a wild yeast infection, etc. We can only analyze the info that you give us and try and help you rule things out, like faulty equipment, etc.

Tap water will not significantly affect a gravity reading. Even very high minerality like 500ppm TDS would only increase the s.g. by about 0.00027.

With a few spare moments during brew day today, I tested two of my hydrometers with distilled water and tap water. Both read 1.000 with distilled, then I checked them with tap water, one still read 1.000 and the other read 1.002. Later in the brew day I checked them both in the wort at different points during the brew ( pre and post boil) and they were identical. There was only a discrepency with tap vs distilled. My point is these aren't highly reliable instruments to begin with, so these readings that we are quoting aren't the most valid in the first place.

The real point I'm trying to make to the OP is take a step back and look at your overall process, anything that you are not 100% sure about, triple check it, then fix it if need be. Trying to chase down one specific thing isn't always the answer, sometimes you do need to make multiple changes at once, even though some people baulk at that idea. You're not going to get everything 100% correct on your 2nd all grain batch...I've got DOZENS...and DOZENS of all grain batches under my belt...and I'm still working out kinks...little by little...brew by brew.

I hope this doesn't come off as pretentious...I'm really just trying to help

 

[BeeSpojj]

To be honest, there's no way we can answer your questions with any degree of certainty. Could it be a wild yeast infection? Possibly. Could it be a bad hydrometer? You already know it's not calibrated properly, so I'd just get a new one. Is it just very high attenuation? Again, possibly.

A couple things to note here.

1) Miscalibration is not always linear...I've seen thermometers that read 3 degrees off at one temp, and 10-12 degrees off at a much higher or lower temp. I've seen scales that do the same thing. Just because your hydrometer is off to a certain degree when the wort is at one concentration, doesn't necessarily mean it's going to be off to the exact same degree at another concentration. You know it's not calibrated properly...I'd just get rid of it.

2) When you calibrate a thermometer, you check it against either iced water or boiling water, because they will be 32/212 degrees F. repsectively. There's no way to tell if that non-digital thermometer that you checked it against was properly calibrated. Not saying it wasn't, but there's only one way to find out.

3) You seem to be looking for the one "Thing" that is driving down your FG. That's not always the case. Could it be one definitive thing, sure. It could also be a number of factors working together that are creating this issue. This is why it's important to double, then triple check everything in your process. For example, you mentioned you fermented at 65 degrees F, was that ambient temp or actual wort temp? A high fermentation temp can increase attenuation. All these little things add up.

No one here is going to be able to look at a few pictures of a hydrometer sample and say for certain that it's a wild yeast infection, etc. We can only analyze the info that you give us and try and help you rule things out, like faulty equipment, etc.



With a few spare moments during brew day today, I tested two of my hydrometers with distilled water and tap water. Both read 1.000 with distilled, then I checked them with tap water, one still read 1.000 and the other read 1.002. Later in the brew day I checked them both in the wort at different points during the brew ( pre and post boil) and they were identical. There was only a discrepency with tap vs distilled. My point is these aren't highly reliable instruments to begin with, so these readings that we are quoting aren't the most valid in the first place.

The real point I'm trying to make to the OP is take a step back and look at your overall process, anything that you are not 100% sure about, triple check it, then fix it if need be. Trying to chase down one specific thing isn't always the answer, sometimes you do need to make multiple changes at once, even though some people baulk at that idea. You're not going to get everything 100% correct on your 2nd all grain batch...I've got DOZENS...and DOZENS of all grain batches under my belt...and I'm still working out kinks...little by little...brew by brew.

I hope this doesn't come off as pretentious...I'm really just trying to help

Awesome, thank you for you reply! I think as a beginner, this is what I needed to hear and it makes complete sense. Being new, I definitely have an open mind and I'm trying to learn as much as I can.

Thank you to everyone giving a reply in this thread, hearing everyone's opinions and thoughts has helped me greatly. Looking forward to brewing my next batch and I think patience and accuracy is going to be my savior!

Cheers!

 

[Boleslaus]

Make another beer. Make it higher gravity - OG 1.050+. If it still reads close to 1.000 then "maybe" you have a wild yeast contamination. I'm going with a miscalibrated hydrometer plus very low gravity to begin with so the margin becomes smaller.

 

[RPh_Guy]

Both read 1.000 with distilled, then I checked them with tap water, one still read 1.000 and the other read 1.002. Later in the brew day I checked them both in the wort at different points during the brew ( pre and post boil) and they were identical. There was only a discrepency with tap vs distilled.

Unless your tap water is over ~4000ppm TDS (pretty unlikely), that 1.002 reading is just a measurement error, not a real change in the tap vs distilled water density.

 

[Day-Day]

Unless your tap water is over ~4000ppm TDS (pretty unlikely), that 1.002 reading is just a measurement error, not a real change in the tap vs distilled water density.

I'd completely agree, that was actually my point.

There was only a discrepency with tap vs distilled. My point is these aren't highly reliable instruments to begin with, so these readings that we are quoting aren't the most valid in the first place.

These are not highly reliable instruments, they include measurment errors, which were probably in my example, and the OP might be experiencing as well...you can't take every single reading as exact and precise.

Make another beer. Make it higher gravity - OG 1.050+. If it still reads close to 1.000 then "maybe" you have a wild yeast contamination. I'm going with a miscalibrated hydrometer plus very low gravity to begin with so the margin becomes smaller.

This also ^ I'd like to see the OP brew a higher gravity beer and see if his FG is still that low.

 

[BeeSpojj]

I'll definitely brew a higher gravity beer to see if it's still an issue. But before I get there I need to work backwards and make sure I can actually get a brew to a proper OG without needing to add anything.

 

[dmtaylor]

It appears you are doing everything correctly! Except maybe for one (okay two) question(s): What sanitizer are you using for your fermenters? What quantities of which sanitizer and water? Some sanitizers are more effective than others. All your evidence suggests you could potentially have a wild yeast infection, because there is simply no other explanation for what you are experiencing.

Okay, a third set of questions: Are you using an airlock? What style? Or how are you sealing your fermenters?