I often hit my OG numbers pretty closely, but I seem to always finish well below estimated FG. Most recent example was a rather simple all-grain American Amber. Beersmith3 estimated OG of 1.046 & I was 1.047. BS3 also estimated FG of 1.011. I used a single pack of Wyeast 1056 that was about a month old. No starter obviously. After 4 days my hydometer measured appx 1.004-1.005. I'll test it again today or tomorrow, and will probably keg it if it remains at that FG meaning it was just 6 days from fermenter to keg. I'm just curious how common it is to almost ALWAYS finish below estimated FG? It seems all of my batches follow that pattern. No fancy fermentation either. Just in my dark basement always around 66 degrees. Anything I need to worry about or no-big-deal?
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bucketnative
Well-Known Member
Are you sure of the accuracy of your hydrometer? In water, it should measure 0.000 at the stated temperature for measurement. My particular hydrometer measures about -0.006 low in water, but I know that so I adjust the number for the bias.
Otherwise, I have found that the programs tend to overestimate FG. I mean, most will tell you that Belle Saison will stop around1.007... fat chance.
Otherwise, I have found that the programs tend to overestimate FG. I mean, most will tell you that Belle Saison will stop around1.007... fat chance.
Dgallo
Instagram: bantam_brews
I typically finish 4-6 points below projected. How low did you mash?
If you read through the yeast spec sheets, they will always have an attenuation range. I think most of the software uses the middle of that range under the assumption that it follows a normal bell-shaped curve. In my experience, the yeast usually performs at the upper end of the range as long as the mash provided sufficient sugars.
Garage12brewing
Well-Known Member
The most important thing... was the beer good ??? I always finish a little lower and I learned over time that numbers arent always that critical. The taste is !
Hydrometer is easy to calibrate. 1.000 in reference temp (60F or 68F depending on the hydrometer), and multi point can be done with table sugar solution- especially if your hydrometer has Brix listed (or convert Brix to SG). % by weight sucrose is degrees Brix. So 10 grams of sugar in 90 grams of water is 10% sucrose, or 10° Brix. Which equates to 1.040. That way you're using a known reference to calibrate it.
HOWEVER I'd suspect your mash thermometer is a big part of your issue, not your hydrometer.
Let experience be your guide. Calculators are seldom accurate with attenuation. I find BeerSmith tends to undershoot all-malt attenuation and overshoot it if you use sugar adjuncts. But that's a pretty significant gap. BeerSmith is usually better than that.
HOWEVER I'd suspect your mash thermometer is a big part of your issue, not your hydrometer.
Let experience be your guide. Calculators are seldom accurate with attenuation. I find BeerSmith tends to undershoot all-malt attenuation and overshoot it if you use sugar adjuncts. But that's a pretty significant gap. BeerSmith is usually better than that.
+1, i've had beers go to 1.000 with a 145f mash before i even started adding gluco to my brews......
Not so obvious, unless you pick up your yeast at the door of the Wyeast Lab. You never can be sure the yeast was treated well during shipping or anywhere along the line before you get it. I make a starter whenever I am using liquid yeast at whatever gravity the recipe is.
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sbsmann
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Okay....my mash was about 151 and it didn't move at all in the 60 minutes rest period. I had two temp gauges on the mash and they both checked out so that I know was accurate. My beers always taste fine, just found it weird that I always finish lower. I suppose I could test my hydrometer, which I have never done. I really only use the thing for FG (I use refractometer for all pre-fermentation stuff).
Checked out....against what?
I've had thermometers that are +/- 5 degree accuracy. That read accurate at boiling AND freezing, but 5 degrees off in strike/mash ranges. In that case your 151 could be as wide as 146-156.
I switched to a Thermapen and my temps and attenuation became MUCH more predictable.
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sbsmann
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Checked out against each other. I feel it would be VERY coincidental that two thermometers were both off by exactly the same amount. Furthermore, I have checked these thermometers against others as well and never had any issues with my mash temps. I feel pretty confident that my lower FG's are not related to my mash temp being grossly misinterpreted.
i'm lazy and don't, so i'll ask....do you actually update your mash profile in beersmith?
edit: and out of curiosity, what base malt brand do you use?
edit: and out of curiosity, what base malt brand do you use?
In your case since from what I understand you put gluco in everything, I'm not sure it's laziness or just irrelevance.
But yes, that could be a factor.
3 degrees farenheight isn't grossly......i just punched in the differnce beersmith calculated on a FG of a beer with a OG of 1.068, and the difference it perdicted between 145f mash and 150f was 1.004 points
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sbsmann
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Good questions and yes I do update the profile based on my desired mash temp. I have several profiles saved based on my most common mash temps. In this particular recipe I brewed, it was pretty simple with must Rahr 2 Row, German Munich Malt and Briess Caramel 60.
My experience with FG has not been so predictable. Using BS2 and now BS3, My FG swings wildly compared to the predictions. Sometimes higher and sometimes lower. Usually withing a few points. I just don't really pay attention to the numbers.
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I used to have the same problem. I changed two things. 1) I brew in a bag and mill my grain with a corona mill. I initially was really pulverizing the grain because I was under the impression that was what had to occur to make up for efficiency when compared to more traditional brew systems. I believe the finer milled grains was allowing the enzymes to convert the starches to simple sugars at a much higher rate than is traditional, ultimately producing beers with a higher og and lower fg. I remedied this by adding washers to expand the gap in my corona mill, giving me still a fine but more traditional crush. 2) I believe I was also beginning to see signs of what would eventually become full-blown infections. I was experiencing subtle off-flavors in some beers and some of my FGs were getting anywhere from 1.001-1.005 no matter the style or mash schedule. Eventually I got 3 consecutive infections and realized I'd been making the rookie mistake of assuming my sanitation was on point when it wasn't at all. I got too relaxed with it and eventually it caught up. I since really stepped up my game in sanitation practices all around. Since remedying those two things I solved the problem with over attenuation in my beers.
