Have a few brews under my belt. Low key set up, 1 gallon batches. I use Brew In A Bag technique with a stock pot and glass carboy. Recently started using a hydrometer. My last two batches had a low original gravity. Most recently an Irish Red. Target OG is 1.063. I came in at 1.024. Used 2.25lb Maris Otter Pale Malt, 5oz Caramel Malt, 1oz Roasted Barley. Steeped in bag for 75 min at 160F (temps did drop as low as 146F during steep). Mash out at 168F for 7 min. Brought to boil and add .2oz Willamette (6%) hops for 60min. Add .2oz East Kent Goldings (4.7%) for last 10min. Stock pot into ice bath to 76F and pitched 1 packet rehydrated Danstar Nottingham yeast. Took low OG measurement prior to pitching. I saw a ton of fermentation activity within 5 hours (actually blew the carboy top even with a blowoff tube). I'm about a week into fermentation. It's slowed but still see a small foam on top of brew. I'm concerned with the low OG. This means a lower ABV%, correct? Any suggestions or ideas as to how to keep my OG on target? I read a little about Dry Malt Extracts being used to raise the gravity, but am not familiar with the process. Ideally it's be nice to not rely on DME additives to fix the brew. Thanks for your input.
The healthy activity you got tells me something, and the layer of krausen you still have a week in tells me something else about that makes me question the accuracy of your reading. First guess is you took the reading at way too high a temperature, and that you got a false reading. The hydrometer is typically weighted to read at a specific temperature. Most of the ones I have used have been weighted for 60ºf. brewersfriend.com probably has a hydrometer adjustment to temp thing on it. Go there and plug your numbers in. But, also. Let's go to some other details you included that are probably more troubling than even that. I'm worried about a couple other things in your process too. I don't know why you decided to mash at such a high temp, and I really don't know why you decided to pitch the yeast you have at such a high temp either. Some yeasts aren't picky about their temp. Most of them, however, are, and your Nottingham more than likely hit primary fermentation at about 80ºf, which is a good 10 degrees above what they are comfortable working in. That's going to be a big issue in what you taste, and what it will do is not going to be pleasant.
I agree that there is probably a reading error on the hydrometer because of the reading at too high of a temp, especially since everything you describe points to a normal fermentation. However, if it turns out that you aren't getting much sugars from your grain as the cause of the low reading, the crush of your grain could be an issue. Do you crush your own grain, or is it crushed by your retailer?
My retailer does crush the grains for me. I take a hydrometer reading after the boil and before transferring the wort to the carboy. Is this not the correct time to measure gravity?
This is the recipe I follow: Recipe Profile OG 1.063 FG 1.015 IBUs 26 ABV 6.3% Boil 60 minutes • 2.25 lbs Maris Otter Pale Malt • 3 oz Caramel Malt (10L) • 2 oz Caramel Malt (120L) • 1 oz Roasted Barley Mash Profile: • 160°F (strike temp) • 152°F (steep temp) • 75 minute steep • 9.5 quarts (9 litres) Mash Out: • 168°F (7 minutes) • 0.20 oz Willamette (6%) for 60min • 0.20 oz East Kent Goldings for 10min • Danstar Nottingham Yeast The one difference is that I do NOT sparge. From what I understand, BIAB technique doesn't call for that. Plus I don't have a false bottom kettle to drain sparge water over. So I don't use the amount of water called for (I think the recipe calls for sparge). I use about 1.5 gal to make up for boil loss and usually I get pretty close to exactly one gallon when it goes into the carboy.
Also I used a hydrometer correction calculator online and my 1.024 reading at 78F still only corrects to 1.026 at 60F.
Have you actually calibrated your hydrometer? I use hydrometer for brewing, measuring coolant concentrations, diesel emissions fluid urea content, and battery acid concentrations. Usually if I have a real wonky reading I find my hydrometer is out of calibration.
When I first received it 2 months ago, it did read 1.000 in water (give or take 0.001). I assume that meant it was fairly accurate. Not sure how I'd even calibrate it if needed as it's a simple glass one, no electronic components.
The typical time to take an Original Gravity reading is at the time of pitching your yeast, which for most ales will be around 65 degrees. You can adjust it for the 60 degree mark if you want, but I never bother since this isn't rocket science. Then take a couple readings (Final Gravity) a day or two apart when you think fermentation is complete. If these two readings show no great movement in the number, then you're safe to package the beer (although it's always a good practice to give the yeast a few days to clean up after themselves). To my knowledge you can't adjust the device. Either get a new one or just put up with using your existing one knowing that it always reads a certain number of points too high or low and adjust accordingly in your data records.
I'm definitely reaching here but 40 points indicates something pretty major. A) Is it possible they did not crush the grains for you? ... though I assume you would have noticed that having brewed a couple times already. B) 160 is kind of a high mash temp though that shouldn't account for a 40 point miss. C) Hydrometers have several markings. So do thermometers. Did you look at the wrong one? I've stared down C a couple times when I should have been looking at F. Once even crushed KGs instead of LBs. I mean it's gotta be something very unusual to miss like that. It's a 1G batch BIAB. Pretty fool-proof. Makes me think it's not a process issue but more of an error somewhere.
When you said you steeped at 160, then the recipe said strike is 160, that's 2 separate things. Did you measure your mash at 160? The strike at 160 to me is indicating that's what your strike water (the one you add to the dry grains) should be 160, not your mash. If that's what happened, then read the mash at 146, panicked and brought the whole thing up to 160, you likely didn't get full conversion - that probably denatured many of the enzymes that unravel the sugars. So it's possible that's what happened. if you measured OG at 74 degrees, it'll make a difference, but not 40 points worth. Still not a bad idea to check your calibration. Also double check your thermometer calibration, at freezing and at boiling.
There certainly is temperature fluctuation during steeping as it's hard to keep a constant temp using a simple stock pot on electric stove. I first put the bag of grains in at 160F (stove off). But during the 75min steep, twice I had to turn the stove on as the temp fell as low as 146F. I removed the grains while the stove was on so my mash out might've been even higher than 168F. If I had to guess, I'd say this temperature fluctuation is the problem. It's just very difficult to correct with my setup, especially during a 75min steep compared to my usual 60min.
I’ve had to raise the temp on a 10g batch BIAB before I started using a cooler. Never missed that big. But speaking of coolers, you can maybe mash a 1G batch in a cheap 2 gallon cooler. Just use the bag in the cooler. Never worry about holding temp again.
You might be on to something there. I'm guessing my hydrometer is like most used for home brewing; a triple scale with readings for specific gravity, sugar and alcohol. @Djallison53 is it possible you read the Brix scale at 24? On my hydrometer, 24 lines up with about 1.067 specific gravity, which would put you pretty darned close to you target OG. You might want to test your hydrometer again in water. It's possible (though it's not happened to me) that the paper scale has shifted inside your hydrometer. If the entire hydrometer sinks below the water line, it's time for a new one; actually two if you stay with the hobby. You won't want to be without when (not if) you break one.
There's 3 markings on my hydrometer. Specific gravity at 60F, percent sugar by weight, and ABV estimate. No Brix. I examined the crushed malts from my brew store. They seem like it's ground well enough. So I think I'll take a step back and meticulously examine the steeping temps. I got a two gallon cooler to steep in so the temps stay consistent. Next attempt will be a simple 1 malt, 1 hops recipe.
