So...many questions here so I'll break down my thoughts. Please don't be offended if I review something you're doing or already know. I'm not assuming anything and either way the extra detail makes sure nothing is missed and can help those just starting out on here.
1. Krausen - Although I most of mine fall I have had one that stuck around and have read it happening with others. In the end although krausen can be used as activity indicator but I'm wary to rely on it. Different strains do different things in different conditions. Your only reliable indicator is a measurement of gravity. Even airlock activity is just a heads to check gravity. A stalled fermentation shows no airlock activity but yet it isn't actually done fermenting. Anyway, you get the picture.
2. Hydrometer - I know you didn't say much about it but in reference to your OG readings one thing I don't know if you've done is a proper calibration to know your hydrometer is accurate. That paper pice can move around in the glass vial if you bounce it on the bottom of the hydrometer jar when putting it in. In a nutshell you get distilled water. Heat or cool it to the hydrometers calibration temp (usually 60F but always noted on the actual hydrometer). Measure the distilled water at the calibration temp. If its not 1.000 then you have to factor that in overtime you do a reading. For instance I have to minus 2 points for every measurement I take. Also, your wort sample has to be at your calibration temp or you need to do a temp adjustment calculation.
eg. My reading is 1.060 when I take a sample. Sample temp is 105F. I need to minus 2 points to start giving me 1.058 then adjust for temp giving me an actual OG of 1.065
The calculation can be done in the tolls section of Beersmith (which I personally use and recommend as a recipe builder and toll resource) or online like the one at
Brewers Friend Hydrometer Temperature Calculator
3. Hydrometer - ***Note: This is bound to be the most controversial section of this post. Some swear that they are only good for OG and not for fermenting or final readings and are very passionate about it (I'm looking at our resident engineer
). I myself think they can be (and are used) both in the pro and home brewer setting but you have to do the work to ensure the accuracy. The big deal is they're really made for judging the gravity of wort but instead the gravity of sugar water containing just sucrose. Because beer wort has more complex sugars then hydrometers are not really ideal. Note that they do make "brewer" hydrometers set and calibrated for what we measure but they're quite expensive and it seems most are digital that do this. Then once you're fermenting you need to factor in as well the alcohol being produced so in comes a calculation to compensate for the alcohol and maltose.
Anyway, back to your refractometer. Note that what you spend also denotes how much you can rely on it without frequently calibrating and checking it. There are many good pages to help you but breaking it down you need to do a calibration with distilled water at the refractometers calibration temp (usually 68F) and use the small set screw to correct it if it isn't reading zero. Many refractometers also have ATC (Automatic temperature correction) to compensate for warm samples. to know thats working I've also heard of people putting a warmer distilled sample on it to see if it reads zero as well once its calibrated. At the least it lets you know that a bit warmer (or colder) sample will be read correctly and if it isn't then in theory you can devise a compensation or always try to have your samples close to calibration temp. After doing that then you need to do some measurements that compare wort reading both on your (calibrated!) hydrometer and your (calibrated!) refractometer. There are several pages again that can help you do this and you can either do it over time (with your brewed wort) or with water and some dme to mix up at least one wort sample if not many (keep dissolving dme and do more readings). The goal here is to arrive at a wort or brix correction factor that is used to modify your prix reading so it is more accurate with the hydrometer samples you've chosen not to take. Note that this correction factor is specific to your refractometer and nobody else's.
You can find more info:
Using a Refractometer
Determining Wort Correction Factor
Brülosophy's take on refractometersFinally all hydrometer readings need to be followed up by punching them into a calculator along with the wort correction factor that you have diligently calculated. If its just wort then thats one calculation. If its fermenting or fermented wort then you have to use the fermenting calculation (or tell it via drop downs) so it knows to factor alcohol into the new equation and you also need the OG so this is why its important to get that reading spot on.
Calculator:
Brewers Friend Refractometer CalculatorSo after you do all this then you can know what your getting and how your getting it. Put it this way, all of the tools we use need calibration and correction and some more than others.
4. Pitch temp - This is the only process thing that jumped out at me. For fermentation the most critical time is the first 24 hours. The yeast probably got going in 6 hours because you were more in the upper end of US-05's temp range. The problem with that is you may (not always) note more ester and 'hot" alcohol notes in your finished beer. a cooler start temp is really desired and then ramping up once the bulk of fermentation is done. I'm also noting that your fermentation temp was lower with can defiantly play on yeast. They don't like getting colder and if they're in the middle of making alcohol then they tend to throw off some bad flavours. Again, this is a maybe but if you taste them when its done then this is a place I'd look at changing. In an ideal situation you cool a few degrees cooler then your planned fermentation temp and then pitch and let it rise to the ferment temp. If you can't get down to your planned fermentation temp or a couple degrees cooler then it is an option to delay pitching and chilling further in a fridge or if you have a fermentation chamber. As long as your clean and sanitized well then you can give yourself a few extra hours before pitching to get it cool enough. Likely better than starting too warm.
5. The wild card - Now, I'm not saying it is but when I look at your apparent attenuation based on some sample wort correction factors then you seem to be possibly over attenuated (IF your 1.058 is 100% correct...if it was actually lower after you make corrections then its not over attenuated...which is why I'm hoping the 1.058 is off). If it's that over attenuated we could be looking at a wild yeast infection which also may be showing in the krausen you still see. If that is the case then the next point is iffy.
6. Kegging in 2 days - Rerun your numbers and do the work. Really, taking a few samples over 3 days helps you know it's not still fermenting. If you're clean then its probably is done fermenting or damn close based on your timeline. If there is an infection then it might keep on going. If you rerun numbers and your over low 80's in apparent attenuation then something is likely up.(
ABV/Attenuation Calculator) Some people report US-05 going further but too far likely means something else got in there. In the end you either wait it out or make a call. If I were you and decided I wanted to take a chance on kegging then taste a sample. If it tastes good the cold crash it and keg. If it IS intact infected then the cold will slow or stop the wild yeast from further attenuating. If its not infected then your good too. Once you keg if you suspect at all that infection existed then when done with this keg and tap you need to go the whole 9 yards to make sure its sanitary before using it again. tear it down and soak or even better replace seals. If all that scares you and you suspect contamination and don't want to clean the shit out of everything later then say your choice is the drain.
Once again...these are just thoughts based on unknown numbers. I hope I haven't freaked you out and that you forget all but the good stuff if the numbers and beer come out fine.
Whew...long message...likely spelling/autocorrect mistakes...sorry...any question please ask...looking forward to an update!
Stephen