Attenuation low. What is everyone doing to get good attenuation?

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Sarobinson426

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Hello homebrewers. I'm hoping for some help and hopefully the answers here this will help everyone out. Attenuation. I have done around 7 batches of all grain brewing with only 2 row base malts, and I can't achieve above 63% attenuation. I have read Gregg Doss's "Exploring Attenuation" and have tried to follow this as a guide.

Milling my grains at 0.7mm with a two roller mill. Recently started doing two millings of the grain (didn't work).

Getting the temperature to 153*F with a mash from 60 to 75 minutes.

I have used pH stabilizer (star san).

I've used small amounts of CaCl and CaCO3 (after the mash). I've tried using spring water. Tap water

Boil is around 60min give or take a few minutes.

In many of the batches I've added 0.2 oz of Williamette hops.

Pitching about half of 11.5g packet (so 5.75g of yeast) of Safale US-05 (supposed to get 78-82% attenuation).

e.g. recent batch was at 1.087 O.G and I've received a 1.032 F.G after a week and a day or fermenting. I did this batch on the stove top.

Having said all this my most recent batch had a mash that ranged from 145.4*F to 153.1*F. When the temp dipped I would put the heat on low and stir to get the temp up. I'm at a loss here guys and I'm not sure how to get a better attenuation.
 

Erik the Anglophile

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How big are your batches? Half a pack for a 5 gallon batch is a serious underpitch.
Have you calibrated your thermometer? I use a glass immersion thermometer that I checked in boiling water, it was off by 2c, so if I want to mash at 66c the thermometer should read 64 etc... the issue could be too little yeast and that you may mash warmer than you believe.
 

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e.g. recent batch was at 1.087 O.G and I've received a F.1.032FG after a week and a day or fermenting. I did this batch on the stove top.
How did you measure the FG? 1.032 looks an awful lot like the FG if taken with a refractometer without doing the calculations for the inclusion of alcohol in the sample.
 

dmtaylor

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Welcome to the HBT forum! Excellent first post! I appreciate the level of detail.

Three ideas you need to followup on:

1) Get a pH meter and check your mash pH. Ensure you calibrate the pH meter. You'll want to be aiming for a mash pH of about 5.4-5.5. It is possible that your water is highly alkaline and mash pH is too high, closer to 5.8-6.0, which can hurt efficiency and fermentability. The pH stabilizer chemical is notoriously NOT very helpful for many people.

2) Calibrate your mash thermometer in both ice water (32 F) and boiling water (look up boiling temperature at your particular elevation above sea level).

3) Calibrate your hydrometer or refractometer in plain water. If you are using a refractometer, then I agree with @RM-MN that this might explain everything. When alcohol is present, a refractometer will only give accurate results if you enter the value into a conversion calculator -- the one at BrewersFriend.com is the most accurate of all.
 

DuncB

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An OG of 1.087, volume of wort unknown, it's a pretty stiff test for that yeast.
Running that wort through a yeast pitch calculator suggests one packet per 5 litres of wort ( provided its an ale ) double it if a lager.

You'd also want plenty of oxygen, plenty of nutrient, good temp control and time.

What does the beer taste like?
 

hottpeper13

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It's all about healthy yeast and most water needs some extra calcium for the mash and the yeast. My softest water profile has 73 ppm's, most I try to get to 100 and a pH of 5.2 for blonde and 5.5 for dark beers. If all are under attenuated and cloudy add more Ca.
 

hotbeer

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I get 84 - 85% attenuation with US-05 in the batches of beer I've been brewing.

Most having a OG in the 1.060 to 1.070 range.

And I don't do most any of the "extra" things you are doing. I just maintain the FV at ambient air temps about 69°F and let the internal beer temp get as high as it wants. Usually about 74 to briefly 76°F during peak krausen.


I too will say you under pitched. For the volumes you'll brew as a home brewer, it's better to overpitch than under pitch. IMO of course!
 
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Sarobinson426

Sarobinson426

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How big are your batches? Half a pack for a 5 gallon batch is a serious underpitch.
Have you calibrated your thermometer? I use a glass immersion thermometer that I checked in boiling water, it was off by 2c, so if I want to mash at 66c the thermometer should read 64 etc... the issue could be too little yeast and that you may mash warmer than you believe.
I'm doing about 1.5 liter "test" batches. I found that doing 5 gallon batches for exbeerimental beers was just too slow too tedious and not very cost effective. Normally brew on a 10G Unibrau. Soooo.... I cut the yeast pitch in half and have done a self made start for most of the test batches (few pinches corn sugar and small pinch diammonium phosphate).
 
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Sarobinson426

Sarobinson426

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It's all about healthy yeast and most water needs some extra calcium for the mash and the yeast. My softest water profile has 73 ppm's, most I try to get to 100 and a pH of 5.2 for blonde and 5.5 for dark beers. If all are under attenuated and cloudy add more Ca.
Ca does help the yeast out since malt isn't Ca++ rich. I read that it does hinder your mash enzymes though so it's best to add after your mash... probably during boil to make a good solution.
 
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Sarobinson426

Sarobinson426

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How did you measure the FG? 1.032 looks an awful lot like the FG if taken with a refractometer without doing the calculations for the inclusion of alcohol in the sample.
I was using a refractometer, and I'm super glad you called me out because I've been reading a ton on this. The best thing I could come up with is that I wasn't getting enough Oxygen into the wort before the pitch. TY.
 
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Sarobinson426

Sarobinson426

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Welcome to the HBT forum! Excellent first post! I appreciate the level of detail.

Three ideas you need to followup on:

1) Get a pH meter and check your mash pH. Ensure you calibrate the pH meter. You'll want to be aiming for a mash pH of about 5.4-5.5. It is possible that your water is highly alkaline and mash pH is too high, closer to 5.8-6.0, which can hurt efficiency and fermentability. The pH stabilizer chemical is notoriously NOT very helpful for many people.

2) Calibrate your mash thermometer in both ice water (32 F) and boiling water (look up boiling temperature at your particular elevation above sea level).

3) Calibrate your hydrometer or refractometer in plain water. If you are using a refractometer, then I agree with @RM-MN that this might explain everything. When alcohol is present, a refractometer will only give accurate results if you enter the value into a conversion calculator -- the one at BrewersFriend.com is the most accurate of all.
Solid advice. The pH was only ever really low like less than 5 ~4.3 after the mash. If I don't use (five star 5^2) stabilizer (thank you day_trppr) it's really low after mash, and I can only imagine that in that doughy mash that the pH is low which was what was effecting my beer; hence, I started using some pH stabilizer.

pH stabilizer works-ish but not as good as the marketing would have you believe.
 
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Sarobinson426

Sarobinson426

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An OG of 1.087, volume of wort unknown, it's a pretty stiff test for that yeast.
Running that wort through a yeast pitch calculator suggests one packet per 5 litres of wort ( provided its an ale ) double it if a lager.

You'd also want plenty of oxygen, plenty of nutrient, good temp control and time.

What does the beer taste like?
I'm not even sure what it tastes like yet, but I will keep you posted!
 

IslandLizard

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The pH was only ever really low like less than 5 ~4.3 after the mash.
Was that with using pH 5.2 stabilizer or without? What kind of pH meter do you use and at what temperature?
Are you adding acid to your water?
What kind of water are you using? Most tap water (as supplied by municipal water companies) is not acidic, as it would corrode supply pipes.
When in doubt you could use distilled water or RO (Reverse Osmosis) water. Those are a blank slate. At least until you get a good grip on the process.

Consumer pH meters should not be used at high temps at all, such as in the mash, it ruins the probe. Besides, any reference to mash or wort pH is typically at room temps (25°C). Many meters will have temp correction over a short range around 25C, and within limits.

Anyway, a mash pH of 4.3 is very low. The best time during the mash process to measure the pH is at the end of the mash, when everything has stabilized. You could try 15-20 minutes in the mash, just for reference, but readings are not very reliable or repeatable. You need to cool the sample, like in an frozen glass or stainless cup.
If I don't use (five star 5^2) stabilizer (thank you day_trppr) it's really low after mash,
Sorry, pH 5.2 stabilizer doesn't help. It's basically snake oil, it can't bring your mash pH to 5.2 (room temp measurement) if it isn't there already.

pH stabilizer works-ish but not as good as the marketing would have you believe.
Exactly!
 

RM-MN

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I was using a refractometer, and I'm super glad you called me out because I've been reading a ton on this. The best thing I could come up with is that I wasn't getting enough Oxygen into the wort before the pitch. TY.
So, now that you know that you need to do a bit of calculation to determine the final gravity when using a refractometer, what do you calculate the final gravity to be?

I love using the refractometer while mashing and getting a pre-boil reading but out comes the hydrometer for final gravity readings.
 

IslandLizard

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out comes the hydrometer for final gravity readings.
I'm doing about 1.5 liter "test" batches.
That's the usual conundrum using a hydrometer with small batches, it takes a relatively large toll on the final beer volume. But you do get a taste too.

Back in the days, when I started out brewing, I used a wine thief to draw a sample, then dropped the hydrometer into the wine thief,* and after the reading, released the beer back to the fermenter.

Later on you learn that yeast already knows what to do, and just letting her ferment for a week or 2 (or longer for higher gravity beers) is the best strategy. Controlling the fermentation temps, toward the lower end of her range, that's where you make better beer.

I do take "suck samples" using a skinny vinyl hose as a siphon. But only when I need to know gravity at some midway point (for other additions) while it also gives me a good taste sample. Those samples don't get returned, of course. ;)

* The practice of dropping the hydrometer into the wine thief caught up with me quickly. One day, the gravity was "unexpectedly" low, and the hydrometer spiraled down like a torpedo, until it bottomed out. Bye, bye, to my first hydrometer... 3 weeks young. 😭😭😭
Luckily all the glass shards and dozens of small steel pellets remained contained inside the wine thief. I stopped doing that, right there and then, it's really not needed.
 

hotbeer

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The best thing I could come up with is that I wasn't getting enough Oxygen into the wort before the pitch. TY
I don't aerate or oxygenate any of my wort that I'm pitching dry yeast into. Unnecessary according to the makers of the dry yeast. Never had any issue that might get back to not aerating the wort.

If the yeast is slurry that you collected from a previous batch of beer, then it's no longer dry yeast. In this case you do need to aerate the wort and treat it like any other re-used yeast.

As for SG samples with a real hydrometer. Use a cylinder jar that is only a few millimeters bigger than the bulb of the hydrometer. I frequently use the tube that my hydrometer came in for storage and protection. Takes very little beer to float it compared to the big cylinder flask that it came with.
 

bwible

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That's the usual conundrum using a hydrometer with small batches, it takes a relatively large toll on the final beer volume. But you do get a taste too.

Back in the days, when I started out brewing, I used a wine thief to draw a sample, then dropped the hydrometer into the wine thief,* and after the reading, released the beer back to the fermenter.

Later on you learn that yeast already knows what to do, and just letting her ferment for a week or 2 (or longer for higher gravity beers) is the best strategy. Controlling the fermentation temps, toward the lower end of her range, that's where you make better beer.

I do take "suck samples" using a skinny vinyl hose as a siphon. But only when I need to know gravity at some midway point (for other additions) while it also gives me a good taste sample. Those samples don't get returned, of course. ;)

* The practice of dropping the hydrometer into the wine thief caught up with me quickly. One day, the gravity was "unexpectedly" low, and the hydrometer spiraled down like a torpedo, until it bottomed out. Bye, bye, to my first hydrometer... 3 weeks young. 😭😭😭
Luckily all the glass shards and dozens of small steel pellets remained contained inside the wine thief. I stopped doing that, right there and then, it's really not needed.
Thats where a tilt comes in handy. Its not that big and would probably work in small batches too. Just that they are about $125 each and somebody doing small batches probably doesn’t want to go there. Nice to see gravity and temp without opening the fermentor though.
 
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I'm doing about 1.5 liter "test" batches.
That's the usual conundrum using a hydrometer with small batches, it takes a relatively large toll on the final beer volume.
It's a test batch.
  • With a test batch, yield (measured by number of bottles) probably doesn't matter.
  • With a normal batch, size the batch to get the desired volume at packaging time, including losses (hydrometer sample(s), ...).

There is no "conundrum" when recipes and equipment are properly sized for the desired packaging volume.
 

bobtheUKbrewer2

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use a refractometer for FG, yes it is slightly inaccurate BUT a hydrometer is slightly inaccurate in the opposite direction. So ....... if refractometer says FG is 1.009 and hyrometer = 1.006 then the true deadly accurate reading is 1.0075 - I have never been able to detect any consequences of these errors when drinking my beer..........
 

dmtaylor

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use a refractometer for FG, yes it is slightly inaccurate BUT a hydrometer is slightly inaccurate in the opposite direction. So ....... if refractometer says FG is 1.009 and hyrometer = 1.006 then the true deadly accurate reading is 1.0075 - I have never been able to detect any consequences of these errors when drinking my beer..........

Uhh... that's a new one. Who told you this?
 

bobtheUKbrewer2

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dmtaylor - say your beer has finished fermenting and your hydrometer reading is 1.010 - the residual "sugars" are lifting the hydrometer, and the say 4% alcohol, having a density less than 1.000 is sinking the hydrometer. But as I said in my post too small an effect to worry about. I just don't like to read that refractometers are inaccurate whilst hydrometers are accurate.
 

dmtaylor

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I think perhaps you are confusing specific gravity with attenuation. There is a difference between the commonly used apparent attenuation versus real attenuation. However, specific gravity is an intrinsic property of an aqueous solution, so when measuring a delta between original and final gravity, the difference tells you not an approximation of ABV, but is actually quite accurate.

You can get very precise results from a refractometer, and convert to specific gravity if you use a good conversion calculator (like at BrewersFriend.com). However in reality, a refractometer is not measuring specific gravity, but rather refractive index, which is a completely different property which is generally proportional to SG. So as precise as we can get it to convert to specific gravity, it's an approximation but might not be completely accurate, especially outside of a reasonable range for SG.

But anyway.
 

doug293cz

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dmtaylor - say your beer has finished fermenting and your hydrometer reading is 1.010 - the residual "sugars" are lifting the hydrometer, and the say 4% alcohol, having a density less than 1.000 is sinking the hydrometer. But as I said in my post too small an effect to worry about. I just don't like to read that refractometers are inaccurate whilst hydrometers are accurate.
A hydrometer that reads SG always measures SG. Doesn't matter what is in the solution. A refractometer measures refractive index, which is well correlated to SG for pure sugar solutions. When you start adding ethanol, which has a higher refractive index than water, but a lower density, the correlation between refractive index and SG breaks down, so you get errors. The calculators available correct for these errors.

SG also correlates well to sugar or alcohol concentration in binary solutions, but when sugar and alcohol are both present, the SG no longer directly correlates to either sugar or alcohol concentration. The ABV calculators correct for this, just like the refractometer calculators correct for the alcohol presence.

Brew on :mug:
 
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Sarobinson426

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So, now that you know that you need to do a bit of calculation to determine the final gravity when using a refractometer, what do you calculate the final gravity to be?

I love using the refractometer while mashing and getting a pre-boil reading but out comes the hydrometer for final gravity readings.
You know I'm not sure. Just looked up a converter but everything is is brix and so is the second one behind it... let me seeee....
 

Andre3000

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You have not told us what equipment you're using for the mash.

Are you recirculating with a pump? BIAB? You said stirring, so I assume BIAB.

Recently I have been chasing the German pilsner and my beers were consistently underattenuated; it was super frustrating. I was recirculating in my BIAB with a pump. Turns out this pump caused all sorts of issues due to compaction of the grain bed, including attenuation and efficiency. Eliminating that pump made a massive world of difference on the final product.

It sounds like you started at 153F. Not terrible for alpha amylase but I would start lower aiming for 145-150 and go for 90 minutes (insulate, do not heat) to rule out the mash time and temp variable. You should hit 80% easily with us05 with that.

Just some ideas.
 

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Back to refractometer...
I'm a small batch brewer as well and a refractometer is real handy in determining whether fermentation has finished. Just by getting the same reading with a couple days difference. No need for a tool in this case.
I will use the tool to get an idea of ABV. If it is out by a bit, who cares? I'm not brewing commercially and I'm sure I can't taste the difference between 4.8 and 5.2 % alcohol ;)
 
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Two refractometer measurements can tell you that fermentation has stopped. To know that fermentation has finished, not stalled, one can compare the measurement to the estimated FG.

With small batches, every drop of beer has a purpose. Most drops are destined for packaging. Some drop hear a higher calling and are destined for the hydrometer sample tube.
 

RM-MN

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You know I'm not sure. Just looked up a converter but everything is is brix and so is the second one behind it... let me seeee....
Many refractometers that read specific gravity are dual scale and read it Brix too. Look through yours and if it shows Brix, find the FG you read and compare it to the Brix reading, then do the calculation.
 

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It seems the refractometer is the big issue here but it seems there is also an opportunity to improve your process with better control over mash temperatures. If you have an unintentional swing of around eight degrees that suggests not great control. The problem is if you're watching the thermometer you're seeing the temperature change at the thermometer only. Unless you have a recirculating mash it is likely some parts are cooler and some parts are warmer (especially when trying to warm up the mash). You may be getting cooler than you think in parts of the mash and too warm for the enzymes in others. I'm not sure what you use as a mash tun but it sounds like maybe a kettle because you're applying heat to raise the temperature. I'd try wrapping the kettle in a sleeping bag or thick blanket and see if that helps stabilize temperatures better.
 

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