Gravity issues/sweet beer

[BrettV]

I'm a partial mash brewer, so I've come to accept that getting accurate OG readings with a hydrometer is a crap shoot. It seems regardless of what the estimated gravity will be, I'm always much higher. I doubt it's because I'm somehow insanely efficient, seeing as the default efficiency for Brewtoad's software is 75%, which is pretty good.

Anyway, I brewed a very simple pale ale/cream ale recently that should have come in around 1054, and instead came in at 1064. I didn't sweat it, though because I've been told that getting accurate readings from my hydrometer when I've added top-up water to the mix can be dodgy. Generally my FG numbers come close to the estimates, which is usually how I can tell I was probably near my mark. I'm not THAT concerned with what the ABV is, anyway. Does it taste good? Great; drink it. However, this time my FG was quite a bit higher than the estimated 1014 at 1020. Also, while I was expecting a nice, dry brew with a floral/tropical aroma from the Simcoe hops. The Simcoe character is definitely there, but the brew is much sweeter than anticipated. No off-flavors or detectable flaws; it tastes clean, just on the sweet side.

This isn't the end of days; I'm sure once it's carbed up in a few weeks it will be guzzled by everyone without much thought, but I'm just wondering how I could have ended up with such a sweet tasting beer. Without TRULY knowing the original gravity, I guess it's left to speculation. I'm thinking either the yeast didn't ferment out all the sugars which is why I only got down to 1020 (although I made a starter, fermentation started pretty quickly, and for the first few days it was VIGOROUS, so all seemed in order there) or possibly both gravity readings were correct, and I got crazy efficiency.

Here are all the pertinents, for those who like to know these things:

Recipe specifications
Batch size: 5 gal.
(Estimated) OG: 1054 FG: 1014 ABV: 5.2% IBU: 42 SRM: 2


Grain bill:
4.75# American 2-row barley mash 60 mins
3# Briess Pilsen DME late boil
0.25# Grain Millers Flaked wheat mash 60 mins


Hops:
0.25 oz Magnum 13.5% AA boil 60 mins
0.25 oz Simcoe 12.7% AA boil 60 mins
0.5 oz Simcoe 12.7% AA boil 15 mins
1.0 oz Simcoe 12.7% AA boil 5 mins
1.0 oz Simcoe 12.7% AA dry hop 7 days

Yeast:
Wyeast 1272 American Ale II

Extras:
1 whirlfloc tablet boil 10 mins

I did a stovetop, BIAB mash. Mashed for 1 hour at ~154F, heated strike water to ~165 and "tea-bag" sparged for 30 minutes. Cooled the wort to around 70 with an immersion chiller, topped up with water, aerated for 2 minutes, and pitched the yeast. It fermented for 1 week in the mid-high 60s, dry-hoppped in the primary for 1 week, and bottled on day 15.

 

[jro238]

For the high og readings: does your hydrometer read 1.000 in distilled water? You can also just try taking a reading of your wort prior to adding extract/top off water then calculating how much gravity the extract adds and how much the top off water dilutes.

A few possibilities jump to mind on the high fg.
1) you say you mashed at about 154. How close are we talking and is your thermometer accurate/calibrated? If it is reading 2-3 degrees low then that could be the problem
2) 7 days plus 1 week dry hop really should be enough time to finish a 1.060 beer given healthy yeast (I usually do 9-10 days primary but whatever). Maybe the yeast just wasn't finished this time. Was fg stable before the dry hop?
3) you got a crappy batch of extract that had been mashed too high.

 

[BrettV]

For the high og readings: does your hydrometer read 1.000 in distilled water? You can also just try taking a reading of your wort prior to adding extract/top off water then calculating how much gravity the extract adds and how much the top off water dilutes.

A few possibilities jump to mind on the high fg.
1) you say you mashed at about 154. How close are we talking and is your thermometer accurate/calibrated? If it is reading 2-3 degrees low then that could be the problem
2) 7 days plus 1 week dry hop really should be enough time to finish a 1.060 beer given healthy yeast (I usually do 9-10 days primary but whatever). Maybe the yeast just wasn't finished this time. Was fg stable before the dry hop?
3) you got a crappy batch of extract that had been mashed too high.

I'd need a refractometer to take a reading before I added extract, because I add that to the mix in the last few minutes of the boil. I could take the measurement before I add top-up water, though, because I've been told that could cause inaccurate readings. Basically no matter how hard you agitate the carboy, there's just no way to completely dissolve everything into a solution which would lead to higher gravity readings. I haven't calibrated my hydrometer in a while, so that's a thought.

As for the mash temperature, I'm not exactly using really high tech, sophisticated equipment. Just a little digital meat thermometer. I've always followed Death Brewer's stovetop partial mash thread, and I aim for a mash temp around 154, but I really don't sweat it if I'm getting a reading of a few degrees difference here and there. It is, after all, still a hobby for me, so I like to keep the stress level low on such things. Would you say that mashing at a higher temperature could potentially cause me to end up with a higher gravity?

Gravity was stable in the last week. It didn't change from the day I added the dry hops to the day I bottled. Fermentation was really active for about 3 days, and then I didn't see so much as a bubble in that airlock for the next 11 days.

 

[Yooper]

A higher mash temperature (154+) combined with extract (less fermentable than some other ingredients) often will lead to a higher FG.

For a more fermentable wort, mashing at 150 will really help. For a sweeter beer with more body, mashing at 154- 156 will give that.

I think that's the whole issue- mashing temperature in the partial mash, as well as using some extract. I have had some extract beers finish at 1.020, and that is where they were done. It's really quite common in extract brewing. Since you're doing a partial mash, you can manipulate that quite a bit by your mash. If you mash 4-6 degrees cooler (assuming your thermometer is accurate, which is unlikely), you should have a more attenuative wort.

 

[BrettV]

I just double checked my thermometer, and it read 32.3 in a glass of ice water, so it's pretty close. I think I'll try mashing at a lower temp next time. I wasn't aware of the issue with extract and lower attenuation. I've only ever been an extract/PM brewer, and this the first time I've ended up with a beer this sweet. I'll experiment. Thanks!

 

[peterj]

so I've come to accept that getting accurate OG readings with a hydrometer is a crap shoot.

Basically no matter how hard you agitate the carboy, there's just no way to completely dissolve everything into a solution which would lead to higher gravity readings.

You can absolutely get accurate OG readings when you're topping up. You just have to make sure you mix the wort up well. It's not really all that hard though. I'm not sure why you think it's impossible. Also, not sure what you mean by not being able to dissolve everything into solution? All of the extract should be dissolved during the boil or at flameout (depending on when you add it). Then as long as you mix up your top off water well there's no reason you won't get an accurate gravity reading.

Would you say that mashing at a higher temperature could potentially cause me to end up with a higher gravity?

As Yooper said this is definitely the case. That's one of the main aspects of all grain and partial mash brewing. Being able to control the fermentability (and thus residual sweetness) of the beer through mash temperature. Here's an article I found with more info on this: http://beersmith.com/blog/2012/12/20/mash-temperature-and-beer-body-in-all-grain-brewing/.

 

[BrettV]

I agitate my wort very well, but I was told by another brewer that even with proper agitation, I likely have stratified wort, and that it's very difficult to prevent, no matter how much you mix/agitate. I've posted about high OG before, and that was the response I got from JLem. https://www.homebrewtalk.com/f36/high-og-444421/ His is the 5th post on that topic. Thanks for the link, it's a good read.

 

[peterj]

No problem, glad you liked the article!

Ehhh, I don't really think it's that difficult. I used to do it all the time when I first started and my gravity readings were always accurate. Just make sure you mix the stuff from the bottom to the top and vice versa. I guess it could be harder in a carboy than a bucket (which is what I was using) but still not "exceptionally difficult". Maybe you are just getting really good efficiency. I've heard of BIAB brewers getting 80-90% efficiency.

 

[jro238]

Sounds like you got most of your answers from others after my post but I'll chime in again anyway because I'm sitting here at work

I meant take a hydrometer reading immediately after sparge. Just cool the sample in cold water before taking the reading. It isn't as easy as a refract but doable (I do it all the time). I also use a meat thermometer for my mash. I check its accuracy every few brews and always take temp readings at several locations in my mash tun and it works quite well.

As for wort stratification (which doesn't sound like a problem you are having): I did all of 2 extract and 1 partial mash before going all grain so my experience with extract is limited. It doesn't seem like it should happen but there are so many newer brewers on here that have problems with hydrometer readings maybe it really does. Taking a preboil gravity/volume and a final volume will get around this though since your extract should add a predictable amount of sugar.

I mash almost all of my beers at 151 or below (except when style calls for a sweeter beer). Plus or minus 2-3 degrees has a much smaller effect on the final beer if you range between 149-152 than if you range between 154-157. Another idea here is to mash in your oven. I haven't tried it but have heard that it is a great way to hold partial mash temp close to constant (just keep the oven on low or warm or whatever lowest setting you have).

Cheers!