Safale S-04 fermented at 20 °C (68 °F) and attenuation too high. What should I expect?

[Nava854]

Right now I am brewing some kind of weird session IPA from this book. The recipe is called “disproportionately hopped”, and by its name you can bet it doesn’t skimp on hops.

For temperature control, we have a fridge and heater connected to an Arduino I programmed myself, but due to a mistake in the code the Arduino went nuts and the temperature slowly raised until it reached 20.3 °C (68.5 °F) at the 24h mark. After I fixed the code the temperature went back to 18 °C (65 °F) at the 30h mark, but it seems that the bulk of fermentation was pretty much done by then (1.010 sg. OG was 1.043).
I have heard that the S-04 yeast creates many undesirable flavors if fermented that high, so I’m kind of worried.

And for those who find some sort of weird satisfaction looking at graphs I have attached the plotted data from the Arduino. I won’t explain all the details, the only thing you need to know is that the red line is the beer’s temperature.


And then there’s the attenuation thing. Gravity has kept going down in the last 4 days. The last measurement was 1.005 and it does not look like it is stopping soon.
One possible factor might be that the mash temp dropped too low (it dropped from 66.5C to 64C or 152F to 147F) and it could have increased fermentability. However, I find it hard to believe this factor alone is responsible for the high attenuation, but I am no expert.


So in short, what kind of beer can I expect from this? Will the S-04 prove to be an unwise choice? Is the low gravity worth the worry?
This is the second batch I’m making and I’ll confess there’s a lot of anxiety going on. I think I should just relax a little.


By the way, here's the recipe.

 

[Nava854]

I just measured the gravity today with a refractometer and I got 1.007, higher than yesterday. This is getting weird. I think it’s either the refractometer’s fault or my fault. Probably my fault.

I just realized I’m trying too hard to make everything perfect, and all these unexpected events are kind of driving me insane because of that. I’m just gonna relax from now on and just wait.

 

[CascadesBrewer]

This is the second batch I’m making and I’ll confess there’s a lot of anxiety going on. I think I should just relax a little.

At this point I would just relax and see how it turns out. 1.005 seems a bit lower than I would expect especially given the specialty malts in the recipe. Your falling mash temp should not have much impact on the fermentability.

Do you have a hydrometer?

 

[bkboiler]

It's cool...call it a brut ipa...
Taste it...s-04 can throw esters if it fermented too hot in my experience.
If it didn't throw esters, the beer will probably be awesome.

 

[DuncB]

As @CascadesBrewer hints are you calibrated and compensating for alcohol with your refractometer?
A hydrometer reading would be useful.

Pitching at 18 and rising to 20 plus isn't too bad and some brews would recommend that. You will get a few more esters but as it's an ipa that might really add. You probably will raise the temp for a day or two now you think it's nearly over as a diacetyl rest anyway.

I initially thought you might be using an ispindel for the gravity. The readings from those can go all over the place due to krausen on the top and or pressure but are good to show the trend and I find fun to watch. Plus you can set warnings about temp as well as gravity changes. Might be something to consider as an easy make for someone building an Arduino.

 

[DuncB]

@Nava854 I notice the book subtitle now. Sometimes there aren't any fools around and that's when it gets complicated.

 

[Nava854]

Thank you for the replies!
Yes, I do have a hydrometer but it needs a sample of 200ml so my plan is to only use it to measure FG when needed.
And yes, I calibrated both the hydrometer and the refractometer with distilled water as well as a "known" dilution of sucrose.
Also, I always take 3 measurements for the refractometer reading (which is something I learned in college, to always take at least 3 measurements). And I always use the brix scale and then compensate for alcohol content.

However, I found a couple of issues with my setup.
When I say a "known" dilution, I mean a dilution of sucrose measured with a cheap precision scale you can get from amazon. I made more dilutions and I found weird results, and I am guessing my
digital scale is not linear, like, at all. So my previous "known" dilution wasn't that known.
I also found that the correction factor I was using for the refractometer wasn't correct.
And I've heard that you should always calibrate with distilled water before measuring, and I only did it once.

But the biggest problem is the refractometer itself. It's supposed to have ATC, but I just found that readings vary wildly between measurements if the ambient temperature is different. It was a cheap refractometer from amazon, so I guess you get what you pay for.
I believe that's the culprit behind the weird increase in gravity. Weather has been kind of crazy these days and different room temperatures could explain it, I guess.
In the meantime will try to find a way to compensate my refractometer for temperature. Or maybe I could get a new one, I don't trust this device anymore.

And by the way, I don't have an iSpindel yet but I'm working on one. It's a very cheap and cool little project, I can't wait for the parts to arrive.

 

[stevehaun]

I run my sample thru a coffee filter prior to using my refractometer. This gives me very consistent results. If I run samples in triplicate, they rarely vary and if they do, it is only by 0.1 brix. I have had good results with S-04 by fermenting at 64F for 72 hours and then letting temp rise to 68F to finish. It is a fast fermenter and drops like a rock. I'll bet your beer will end up ok.

 

[DuncB]

Let us know the outcome.

 

[Nava854]

Just an update.

Today was bottling day. I took the FG reading with a calibrated hydrometer and after compensating for temperature it measured 1.007, which it’s still low but not as attenuated as the previous reading suggested.

Also we tried the uncarbonated beer and we all agreed that the body was rather thin, but it didn’t have such a bad estery taste as I was expecting. It was weird tasting but quite good in fact (however the hop aroma was a little bit underwhelming).

To add body we tested different amounts of maltodextrin on small beer samples and it made a huge difference. We all prefered the recommended amount of 1/4 lb per 5 gallons or 6 g/L.

Up to this point I can say I’m quite happy with the results. Can’t wait for the beer to carbonate.

 

[Genuine]

I was going to add to this that I once made a pale ale and terribly overshot my mash temp...long brew day short...the beer ended up ending at 1.020 instead of the intended 1.010 - brought it to homebrew club to see what my fellow brewing friends thought....After tasting, everyone said it tasted dry and crisp...and couldn't believe that it actually ended at 1.020. They didn't notice or pick up on any "sweetness" from a higher finishing gravity.