This was an extract IPA w/ steeped grains and hop additions at 60, 15, 5, and FO. Target gravity was 1.066. I measured 1.063 after BeerSmith2 converted 15.8 Brix. Had I boiled longer, thereby concentrating the wort through evaporation, I could have hit my target, yes? If so, then at what point in the hop schedule is it best/not best to extend the boil? Also, after 7 days of fermentation, I am now at 8.0 Brix, which converts via Sean Terril's calculator to 1.014 (well, 1.0139 actually). BS2 estimated a FG of 1.015. I am glad have the 1.014, but nonetheless wonder how to interpret the difference. Healthy starter? Lower OG than anticipated? Both? Other? Thanks!
Yes, boiling longer, and thus concentrating the wort, results in higher OG. But did you by any chance end up with more than 5 gallons of wort post boil? Of if this was not a full boil, was your top-off water completely mixed with the wort before you measured gravity? All other things being equal, including rate of attenuation, a lower OG will result in a lower FG. But even without a change in OG, it's not uncommon to not hit exactly the FG you were expecting. Especially when a brewing program is providing the estimate. Beersmith knows nothing about the fermentability of your wort. It just uses some assumed average attenuation for the yeast strain, which is not quite useless, but is far from precise.
Target was 1.066 and measured was 1.063? Not enough of a difference to worry about. Too many small variables could produce that slight of a difference: rounding issue in the calculations on the recipe and/or converting brix; minor difference in boil off; you used a different brand of grain than you put into BS2; the grain this harvest has slightly lower extract potential than what BS2 defaults to; initial gravity reading was still warm enough to throw off the reading; etc. Case in point: I used a different calculator to convert your 15.8 brix and got 1.0654. (http://onebeer.net/refractometer.shtml)
Thanks for the replies, fellas. Makes good sense. Interesting to see that other Brix conversion, for sure. To Vikeman, it was a full boil and I actually ended up with probably a little less than 5gal of wort. Hitting 5gal post-boil is actually something that has eluded me me so far. I think it's because I seem to always be brewing in drastically different ambient temperatures. This brew, for example, was done at about 18-20'F. The last one I brewed was at around 60'F and the one before was inside at 75'F. Still, though, the original question stands: at what point in the hop schedule is it best to extend the boil if necessary/desired? In this instance, I am guessing between the 60 and 15 min additions so as to not lose flavor/aroma I aim to derive from the late additions. However, foreseeing a diluted solution that would require extra boiling time that far in advance seems pretty tough without dozens of batches under your belt on a consistent system (mine is still being dialed in). Any helpful workarounds, though, or otherwise useful habits to build or observations to make? Cheers.
If you know your boiloff rate, and you want to use all the wort, then delaying the first hop addition (and all the rest) would be the way to go. In other words, extend the boil at the beginning. But if you know the boiloff rate and you're making extract batches, it's pretty easy to control the starting volume, so it wouldn't be necessary to adjust at all. Also, it sounds like you're getting less than 5 gallons at the end, not more, so it is odd that your OG is coming up short with an extract batch. Is it a kit? If not, what assumptions are your software making about fermentables per pound of extract? There's no substitute for learning/dialing your system. But I would concentrate first on figuring out an average boil-off rate. Edit: regarding target OGs with recipes containing steeped grains... the yield (in points per pound) from steeping is sometimes less than when mashing. So your software could be making bad assumptions there too.
Aaaaaannnnnd for my next structural alteration: going AG on the next batch. Perhaps this does not bring me all the way back to square 1 in regard to (re)learning how my gear works in concert, but it's pretty darn close. That said, I am much happier to be nailing down an AG set-up from this point forward than the extract system I cut my teeth on. L.
I have found the transition to All grain to be a tricky one. I have 2 batches so far and suspect it will take 2 or 3 more to get the system all dialed in. Get some brewing software it was a big help the second time around for helping me understand an account for a lot of things a new AG brewer would not know they needed to factor in.
Were you off post or pre-boil? for post boil: To put it into perspective to go from 1.063 > 1.060 you needed to boil of .29 gal or roughly a quart. I imagine that in well in the window for different boil rates. pre-boil: That's about a 4% difference in efficiency. That can easily explained without exposing any big errors. I vary that much when going between big and small beers.
All good points mentioned above. Estimates given by software/calculators are just that: estimates. Another point to consider is the instrument you are using to measure your gravities. A few gravity points either way could very well be within your instrument's inherent margin of error for accuracy.
This is a great question, and one I have been working on as well. Extending the boil at the end seems like it would mess up the 15 minute and later additions of hops. All grain system, I have found it hard to determine the boil off after about 8 batches, but I am getting closer, but more to the question at hand.... increasing the boil time near the end of the boil due to lower gravity than expected. I always assume my mash efficiency is low, so I add more grain, so that I more likely to hit the preboil volume and have a high enough pre boil gravity. As I approach the desired pre boil volume I am testing the gravity. (I am using a refractometer and cooling the drops of wort for a minute or so) If its too high I stop sparging and top off the volume with some system water (from the liquor tank) and test again If it seems to be low then I hit my volume and try to determine how much DME to add. Question for the experts, and one way to change the gravity without additional boiling..... How late do you add DME? When I make a starter it boils for 15 minutes, so I guess that seems to be the shortest time.. How about cane sugar?
You don't have to boil for 15 minutes. I wouldn't hesitate to add DME or sugar with only 5 minutes or even less to go. Timewise, I'd be more concerned about getting the DME fully dissolved than I would about whether it boiled long enough to sanitize.
As others have said, a .003 difference in gravity really isn't anything to worry about. When factoring in grain weights, mash temp / time, boil etc, that actually seems to be within the margin of error. You can adjust things up and down with water or extract, but in this case I personally wouldn't. Once everything is done, you probably won't notice any difference in the final product.
So when do you guys take gravity readings? Pre-boil, post_boil, pre topping off carboy with water, post topping off carboy with water? All of the above? Which reading do you care about the most? Your last reading?
I wouldn't even blink over 0.005. Well, eventually I would blink, but only because my eyes were getting really dry.
For me, generally post boil, after cooling. Sometimes I take various readings at various times, but the post-boil one is the one that gives you the most info (IMO). The OG of your fermenting wort is the one that really counts, right? Once my new system is up and running, I will take various readings and be extra careful about measurements until I get my system dialed in. After that, I'm still not going to worry about +/- 0.005. For one thing, the thought that a batch might be a quart or so off in either direction really isn't a big shocker, especially if you're not accounting for every possible variable (which I don't). For a five gallon batch, being off by a quart of water could make a difference of 1/20th of your gravity points (above that of pure water), which could easily account for a 0.005 difference in OG.
