Can’t hit my final gravity

[Joeymacca]

Hi everyone. I just wanted to pick the brains of this community to see if I can figure why I can’t seem to get any of my beers to go below 1.020 FG. This has been an ongoing issue for months now. Many different styles. I hit my OG without issue. But fermentation always stops at 1.020. Some details:
- I do brew in a bag
- Recipe volume is 5.5 gallons
- Most recipes I make are between 1.040 and 1.060 OG and I am always within a couple points if this
- I mash my recipes at 154F for 60 mins
- I’ve fermented cold (60F) and warm (75F) to see if it would make a difference. Still stops at 1.020
- I’ve tried dry and liquid yeast, doesn’t make a difference. Still stops at 1.020
- I do not do a yeast starter
- I do not quickly cool my wort after boiling. I leave it to cool overnight then pitch my yeast.

The beers still turn out to be beers, but it’s bizarre to me that I have had 10+ recipes in a row all stall at exactly 1.020. Anyone have any thoughts on why this might be consistently happening? Thank you!

 

[DBhomebrew]

With what tool are you measuring final gravity?

 

[Brewsmith]

And can you give a recipe?

 

[lumpher]

Sounds like a problem with whatever is being used to measure fg. That's where I'd start.

 

[Geezer-Glide]

Check your mash temperature at different places in the bag. Stratification might be a problem. Higher mash temperatures result in fewer simple sugars and more complex sugars that the yeast can not break down.

 

[oakbarn]

Check your mash temperature at different places in the bag. Stratification might be a problem. Higher mash temperatures result in fewer simple sugars and more complex sugars that the yeast can not break down.

Said he was hitting OG so not the issue. It could be an equipment problem. Get a cheap hydrometer and see if it reads different, We have a final gravity hydrometer to take the FG which we think is worth the money.

 

[oakbarn]

I just saw in another thread where Winsor yeast is stopping at 1.020 (like it's quitting time).

 

[mac_1103]

Said he was hitting OG so not the issue.

Don't unfermentable complex sugars contribute to SG?

 

[oakbarn]

Yes they do, but he is mashing at 154 which will have a minor amount, but maybe the OP should mash at 152- 148 and see if there is an issue with unfermentable.

If the OP gave a Full Recipe, someone with Beer Smith 3 might give him an idea of Projected FG based on the Mash profile.

 

[DBhomebrew]

At this point, Occam's razor says refractometer without a calculator. Until that's cleared up, we don't know there's a problem. It's the equivalent of "Is it plugged in?"

 

[Joeymacca]

Here is the most recent recipe I made. 5 gallon batch. It’s a Session Amber Ale. I use a hydrometer to measure my OG and FG. OG was 1.050. FG was 1.020 (according to the hydrometer). I will say that I am pretty sure the hydrometer is giving accurate readings as I made a milk stout recently that stopped at 1.020 and it definitely tasted far too sweet with very little alcohol. So the way the beer tastes does seem to correspond with the high final gravity, but I suppose the hydrometer could be part of the issue.

7 lb 2.9 oz​	Pale Malt (2 Row) US Mash (76.5%) - 2.0 SRM​	Grain​	1​	76.5%​	0.56 gal​
13.6 oz​	Caramel/Crystal Malt - 20L Mash (9.1%) - 20.0 SRM​	Grain​	2​	9.1%​	0.07 gal​
9.1 oz​	Carared Mash (6.0%) - 20.0 SRM​	Grain​	3​	6.0%​	0.04 gal​
5.7 oz​	Acid Malt Mash (3.8%) - 3.0 SRM​	Grain​	4​	3.8%​	0.03 gal​
4.5 oz​	Cara-Pils/Dextrine Mash (3.0%) - 2.0 SRM​	Grain​	5​	3.0%​	0.02 gal​
2.4 oz​	Roasted Barley Mash (1.6%) - 300.0 SRM​	Grain​	6​	1.6%​	0.01 gal​
0.89 oz​	Goldings, East Kent Boil 60 min (17.0 IBUs)​	Hop​	7​	17.0 IBUs​	-​
0.22 oz​	Magnum Boil 30 min (7.9 IBUs)​	Hop​	8​	7.9 IBUs​	-​
0.44 oz​	Goldings, East Kent Boil 10 min (3.1 IBUs)​	Hop​	9​	3.1 IBUs​	-​
0.44 oz​	Hallertau Whirlpool 60 min at 170.0 F (1.3 IBUs)​	Hop​	10​	1.3 IBUs​	-​
1.0 pkgs​	American Ale Wyeast Labs #1056​	Ale yeast ​

 

[balrog]

Does the hydrometer measure 1.000 at its calibration temp with clean or distilled water?

 

[grampamark]

Putting the recipe into Beersmith gets a predicted OG of .048 and FG of .012 for an ABV of 4.7. The OP’s numbers put his beer at just under 4%. That’s not exactly an epic fail, and I’m inclined to agree with the measurement error scenario.

The amounts in the Beersmith presentation differ by a tenth, or so, for some ingredients because the quantities are entered into the app as pounds and converted to ounces after the amounts are entered. I was too lazy to go back and modify the entries by a hudredth, or so of a pound.

Edit-I went back and corrected the amounts to match the OP’s recipe, and included the acid malt I left out the first time. The gravity numbers didn’t change.

 

[Joeymacca]

I tested my hydrometer and the calibration seems a bit off. I’m getting 1.002 in water. So not a huge amount. As I mentioned before, the beers taste fine but I certainly feel like they are lower in alcohol. The one thing I’ve been considering is doing a yeast starter for my next brew. I’ve never done one so I’d be curious to see if that makes a difference.

 

[bracconiere]

are you familar with refractometers? and know they're different then a hydrometer? sorry to ask, but i want to ask what does your 'hydrometer' read on the left side....

edit i ask because, the 3 BRIX difference would be 1.011, which would be a FG of actually 1.009....? i "think"?

 

[Bobby_M]

19.1% Dextrine heavy malts, mashed at 154F and a single pack of liquid yeast of unknown age. I'm not surprised at all with an FG of 1.020.

I would first recommend checking your thermometer in both a stirred icewater slurry and at boiling to see how your thermometer calibration looks. You might think it's 154F mash temp but if it's really 158, that's one explanation.

With extreme consideration of the yeast pack's manufacture date in mind, use a yeast pitch calculator with the "calculate viability" button checked and the manufacture date input properly. See what it says. I'm 100% sure it wouldn't suggest a single pack is good enough. With an adequate pitch rate and a ferment temp in the middle of the target range, you should see a 1.050 beer ferment to 1.020 within about 3-4 days. If it took longer than that, pitch rate is likely at least partially at play.

 

[Geezer-Glide]

Just another thought but I get better fermentation after aeration with a compressor using a filter and air stone If you mentioned aeration, I missed it.

 

[madscientist451]

Hi everyone. I just wanted to pick the brains of this community to see if I can figure why I can’t seem to get any of my beers to go below 1.020 FG.
- I do brew in a bag

If you are getting consistent FG of 1.020, it may be your mashing procedure. Here are some suggestions:
-Check your thermometer, maybe get a new one.
-Stir the mash every 15 minutes and check the temperature. If you are losing temperature, maybe you need to insulate your BIAB vessel better during the mash?
-I used to be real fussy with my mash temps and stir often and check temps, but these days I use my smooth top electric range, which holds heat for a while, wrap up the kettle in an old coat and don't mess with it.
-Try extending your mash time, I've done overnight mashes when I'm trying to get a real dry beer.

 

[dmtaylor]

I would first recommend checking your thermometer in both a stirred icewater slurry and at boiling to see how your thermometer calibration looks. You might think it's 154F mash temp but if it's really 158, that's one explanation.

This. Calibrate your mash thermometer in both ice water and in boiling water, keeping in mind your elevation because water boils at different temperatures based on how high up you are on the planet, this is all very important. If your mash temperature is off by 4 or 5 degrees, there goes your attenuation.

 

[ncbrewer]

I would first recommend checking your thermometer in both a stirred icewater slurry and at boiling to see how your thermometer calibration looks. You might think it's 154F mash temp but if it's really 158, that's one explanation.

I found calibration in icewater to be harder than I expected. It was hard to get the ice water to equilibrium at 32F. It seemed to work best with crushed ice, and the cup/bowl completely filled with ice before adding water, and adding more ice after adding the water. It seemed that the ice had to be completely packed into the cup/bowl.

Also, some thermometers just aren't very accurate. Here is the accuracy statement for one that I checked on:
We hereby certify that the Digital Candy/Deep Fry Thermometer, Taylor Model 9839 was manufactured, calibrated and inspected to meet design requirements. Accuracy of this instrument, when used in the manner for which it was intended, is as follows:

Range: -40° to 500°F /-40° to 260°C

Accuracy: -40° to 120°F ±4°F (-40° to 49°C ±2.5°C),

120° to 185°F ±2°F (50° to 85°C ±1.5°C)

185°to- 500°F ±4%(85 to 260°C ±4%)

 

[Bobby_M]

I found calibration in icewater to be harder than I expected. It was hard to get the ice water to equilibrium at 32F. It seemed to work best with crushed ice, and the cup/bowl completely filled with ice before adding water, and adding more ice after adding the water. It seemed that the ice had to be completely packed into the cup/bowl.

Yeah, crushed ice and then water to cover it and especially important is to constantly and vigorously stir the slurry with the temp probe. I don't recommend using any analog thermometers since even a $20 digital is going to be faster and more accurate.

 

[ncbrewer]

I don't recommend using any analog thermometers since even a $20 digital is going to be faster and more accurate.

I'm not impressed with the +/- 4F on the Taylor Model 9839.

Edit: +/- 4F in the -40 to 120F range

 

[dmtaylor]

I have a thermometer that if memory serves goes from about -20 F to 250 F or something like that. I don't need a candy thermometer that goes to 500 F -- that seems like it would inherently add inaccuracy.

Lucky for me, at one end my thermometer reads a little low by 2-3 F, and at the other end it reads a little high by 2-3 F.... such that at mash temperature, I figure it's within 1-2 F accuracy, hopefully.

 

[mac_1103]

Yeah, I have a feeling that my old analog thermometer that came with a NIST traceable calibration certificate is a little more accurate than a $20 digital, even if it is kinda slow.

 

[oakbarn]

Ice bath:

Proper Ice Bath

If you have a really good thermometer you can check the one you are using against it,

I like to check my Mash Thermometer at 155 F against my certified Thermapen.

I Check my Fermentation Thermometer at 50 F, 60 F, and 70 F. I note any discrepancies.

If you only use one Thermometer check it at all temperatures where you need it (Mash, Sparge, Fermentation)


Even a Cheap Digital Thermometer is probably a lot more true than any analog ones. I found that those that come with kettles almost useless. They need to be calibrated BEFORE every brew as they tend to drift.

If you use BruControl, it has a place for correction for any the Thermometers!

 

[Deadalus]

Have you been using that pale malt in each of the brews? What brand is it? I had been using Briess Brewers Malt 2-row and switched to Briess Pale Ale 2-row and the diastatic power of the Pale Ale malt is a significantly less than the Brewers Malt. When I used the Pale Ale malt at around 75-80% with other malts (and adjuncts) lacking diastatic power, I would have difficulties reaching target gravities. (I might be saying the same thing as BobbyM but I am not sure if Dextrine heavy malts implies low diastatic power.) Not your problem as stated but then when I mashed at full body temps (154) I would end up around 1.020 like you. However I don't BIAB, I have a 3 vessel system. I have also had temperature probe variability in the past but can't really detail specific outcomes definitively but I do suggest making sure your thermometer(s) are well calibrated, particularly when brewing light and full body beers as being off could lead to being too low or too high. I would also recommend trying a lower mash temperature (148F) and see what happens.

 

[oakbarn]

And, the Elevation VS Boil Temp is a WAG. The boiling Temperature is related to Pressure (which is why Elevation is a WAG) although still part of Calculation. The Boil Temp will change during the day, but the swing is very small normally unless a Front comes thru. Find the nearest airport METAR and it will list the current Pressure. The easiest calculator if you know your pressure and elevation is:

Find Your Boiling Point

You can get a free iPhone App named Ski Tracks that will tell you your exact elevation, There may be other apps. My Brewery is at 681 feet. Right now the pressure is 29.81 " of Hg.

My boil temp is 210.6 F right now.

 

[Bobby_M]

Yeah, I have a feeling that my old analog thermometer that came with a NIST traceable calibration certificate is a little more accurate than a $20 digital, even if it is kinda slow.

There's always an exception. I started selling the CDN DTQ450 thermometers because I tested a case of 12 units against the $95 Thermapen and they were all within 1F at 150F. That's a $17 thermometer.

Most bi-metal dial thermometers have an accuracy spec of +/- 2% of the dial range. 20-220 would be a swing of 8F.

 

[TheMadKing]

There's always an exception. I started selling the CDN DTQ450 thermometers because I tested a case of 12 units against the $95 Thermapen and they were all within 1F at 150F. That's a $17 thermometer.

Most bi-metal dial thermometers have an accuracy spec of +/- 2% of the dial range. 20-220 would be a swing of 8F.

You take that back!

My thermapen has a back light, a rotating display, is 100% waterproof, and I haven't changed the battery in 4 years.

It's not about the top speed, its about the ride

 

[oakbarn]

Certified:

NIST Traceable Non-Mercury Thermometers, Spirit, -1 to 101°C, Certified at 10°C 20°C, 25°C, 37°C, 56°C, 70°C, 80°C, 90°C, 100°C, Immersion 76mm, 450mm SKU : ACC10053BLSFC
$771.55

I will buy from Bobby M: CDN Digital Thermometer LONG PROBE DTW450L

at $21!

 

[mac_1103]

Most bi-metal dial thermometers have an accuracy spec of +/- 2% of the dial range. 20-220 would be a swing of 8F.

Yeah those things are worthless. No argument from me.

NIST Traceable Non-Mercury Thermometers, Spirit, -1 to 101°C, Certified at 10°C 20°C, 25°C, 37°C, 56°C, 70°C, 80°C, 90°C, 100°C, Immersion 76mm, 450mm SKU : ACC10053BLSFC
$771.55

I'm a retired scientist. Spend a good part of my career in academia. You would not believe some of the **** that got thrown away when old profs retired (or died).

 

[Bobby_M]

You take that back!

My thermapen has a back light, a rotating display, is 100% waterproof, and I haven't changed the battery in 4 years.

It's not about the top speed, its about the ride

I have two thermapens in my collection but for people who don't see the value, there's a middle ground that is reasonably good.

 

[Joeymacca]

If you are getting consistent FG of 1.020, it may be your mashing procedure. Here are some suggestions:
-Check your thermometer, maybe get a new one.
-Stir the mash every 15 minutes and check the temperature. If you are losing temperature, maybe you need to insulate your BIAB vessel better during the mash?
-I used to be real fussy with my mash temps and stir often and check temps, but these days I use my smooth top electric range, which holds heat for a while, wrap up the kettle in an old coat and don't mess with it.
-Try extending your mash time, I've done overnight mashes when I'm trying to get a real dry beer.

Thanks for these suggestions. I’ve been mashing at 154F for 60mins, stirring once at 30mins and checking the temp. I insulate the kettle with a blanket but sometimes find it drops down to 150F after 30mins so I temp back up.

I think I’ll try your suggestion of a longer mash time and checking the temp more often. Thanks!

 

[Joeymacca]

Have you been using that pale malt in each of the brews? What brand is it? I had been using Briess Brewers Malt 2-row and switched to Briess Pale Ale 2-row and the diastatic power of the Pale Ale malt is a significantly less than the Brewers Malt. When I used the Pale Ale malt at around 75-80% with other malts (and adjuncts) lacking diastatic power, I would have difficulties reaching target gravities. (I might be saying the same thing as BobbyM but I am not sure if Dextrine heavy malts implies low diastatic power.) Not your problem as stated but then when I mashed at full body temps (154) I would end up around 1.020 like you. However I don't BIAB, I have a 3 vessel system. I have also had temperature probe variability in the past but can't really detail specific outcomes definitively but I do suggest making sure your thermometer(s) are well calibrated, particularly when brewing light and full body beers as being off could lead to being too low or too high. I would also recommend trying a lower mash temperature (148F) and see what happens.

I’m not sure of the brand. My LHBS just lists it as Premium Canadian 2-Row Barley Malt (Pale Malt).

With that said, I’ve had this issue with 2 row and Maris Otter as my base. I’ll take your suggestions of trying to mash at 148F. Thank you!

 

[Deadalus]

I’m not sure of the brand. My LHBS just lists it as Premium Canadian 2-Row Barley Malt (Pale Malt).

With that said, I’ve had this issue with 2 row and Maris Otter as my base. I’ll take your suggestions of trying to mash at 148F. Thank you!

If you remember next time you are there check the brand name and then you could look up the grain information. Like you yourself are thinking, I was wondering what might be in common for all your brews. I was wondering if maybe you bought a full sack of pale malt. I have a 55 lb sack of Muntons Maris Otter which I hadn't looked up but its diastatic power is 62. That's lower than the Briess Pale malt which is 85 while the Brewers Malt from Briess is 140. Manufacturer is important because even for the same type of malt the diastatic power can vary. Your recipe that you posted isn't really borderline though you have slightly over 75% base malt and it was a pale malt. The recipe I was thinking of that I had trouble with the most actually had Maris Otter in it at 66% with 8% wheat, mashed at 156F. I didn't mind it being full bodied but I missed my target OG by quite a bit. I may have overshot too I was having some difficulty calibrating my temperature probe for an indeterminate period.

I'm not a BIAB brewer, but one item that stuck out in my reading about the process that I recall was that the method tends to produce fuller bodied beers. Unfortunately, I haven't seen this mentioned frequently here so I don't have a good understanding of the why but I think it has something to do with the grist ratio. I mention it because you have stated that you are mashing at 154F which in itself is the temperature region for fuller bodied beers (fewer fermentables).
Anyway, definitely try mashing at 148, maybe pick a style with a fairly simple grain bill which is suited for a lighter body and see how it works out.

 

[madscientist451]

Thanks for these suggestions. I’ve been mashing at 154F for 60mins, stirring once at 30mins and checking the temp. I insulate the kettle with a blanket but sometimes find it drops down to 150F after 30mins so I temp back up.

I think I’ll try your suggestion of a longer mash time and checking the temp more often. Thanks!

So the only reason I was suggesting checking your mash temp more often was to see what your heat loss is. By stirring and checking your temperature, you are actually causing more heat loss. What works for me is to hit my mash temp and then walk away, go do something else. When you heat the mash back up, some of the mash may be going higher than you want (depending on your method).
Maybe describe your mash method? Are you adding the grain to the pre-heated strike water? Are you bottom heating the mash after the grain is in?
Laying a piece of foil on top of the mash will keep some heat in and putting a bungy cord around the blanket helps as well.
If I'm in a hurry, I stop the mash after an hour, but sometimes I'll let it sit for 2 hours or longer. I've also done short and shoddy 30 minute mashes and the beer comes out OK, and many brewers say that conversion actually doesn't take an hour. But if you are getting consistent higher attenuation than you want, then I'm thinking there something going on with your method.

 

[RM-MN]

19.1% Dextrine heavy malts, mashed at 154F and a single pack of liquid yeast of unknown age. I'm not surprised at all with an FG of 1.020.

Thanks for these suggestions. I’ve been mashing at 154F for 60mins, stirring once at 30mins and checking the temp. I insulate the kettle with a blanket but sometimes find it drops down to 150F after 30mins so I temp back up.

I see three potential problems that together can make your FG higher than you want. Bobby M listed one of them, dextrine malts. You don't need Carapils with all grain because you can control the amount of dextrines by manipulating the mash temp so ditch the Carapils.

When you add heat to an already converting mash, unless you stir vigorously all the time the heat is applied you are getting hot spots that denature the very enzymes needed for conversion.

You mentioned getting your grains from your LHBS. If you have them mill them for you the quality of the milling is always suspect as many of them will set the mill to keep the people who use a conventional mash tun from having a stuck mash or sparge. That coarser milling takes longer to fully convert and thus require more time. Since your mash hasn't fully converted you add heat to keep the temperature up but as I mentioned above, you may be defeating yourself by denaturing the enzymes. If possible, ask for the grains to be milled finer or double milled and forget about adding heat. Finely milled grains can have their starches converted to sugars incredibly quickly, much quicker than the hour that you try to mash.

 

[dmtaylor]

And calibrate your mash thermometer (I haven't seen the OP reply that he's done that yet).

 

[Joeymacca]

And calibrate your mash thermometer (I haven't seen the OP reply that he's done that yet).

I tested the thermometer today (ThermoPro digital thermometer). 33.4F in ice water. So I’m guessing it’s not a thermometer issue?

Looks like I have a few things to try. Longer mash. Lower mash temp. Have the LHBS mill the grains twice. Limit dextrine heavy malts.

 

[bracconiere]

Certified:

NIST Traceable Non-Mercury Thermometers, Spirit, -1 to 101°C, Certified at 10°C 20°C, 25°C, 37°C, 56°C, 70°C, 80°C, 90°C, 100°C, Immersion 76mm, 450mm SKU : ACC10053BLSFC
$771.55

I will buy from Bobby M: CDN Digital Thermometer LONG PROBE DTW450L

at $21!

https://www.homebrewtalk.com/threads/how-about-a-meme-generator-thread.654449/post-10203158