FG too high

Post #1 made 3 years ago
Hey guys, I am brewing an Amber Ale, expected OG:1.060, FG: 1.016. Well, I got the OG, but the beer has been in the primary for 11 days and during the last 3 days, the FG is 1.032.
So, it is really different from the expected. This is my second brew that this happens, the last one was a Belgian Blond Ale, expected FG: 1.017, real FG: 1.028.
I don't start the dry yeast and I keep it at the refrigerator before using. I do 8 or 9 liters batch and use half of the dry yeast package. The ambient temperature it is around 22 C (oscillating from 20C to 24C). The mash temp for both batches was 66C, I do not mash out.
I bottle the Belgian Blonde and did not have any bombs, the beer tasted really nice, but with a less alcohol content.
Any ideas what could it be? I am almost adding the other half of the dry yeast package (it is a US-05), thinking that the problem is the small amount of yeast. On the other hand, the problem could be that there is no more fermentable sugar on the wort.
Well, any ideas are useful, I am really confused over here.

Post #2 made 3 years ago
Andre, Was your mash temperature at or above 158F/70C?????

If so, you may have a lot of Unfermentable Sugars, as you said.
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Post #3 made 3 years ago

Make sure you have more than one thermometer. Don't trust any of those buggers. You may have been to high as Joshua indicated? Stir a few times in a 90 minute mash. That should do it?
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Post #4 made 3 years ago
Wow! Those are wild FG figures and I think Josh and Bob have nailed the most likely culprit.

We really need to emphasis how unreliable and how important mash thermometers are more than we do. The best info on this thermometer variability is here but what that link does not emphasise is how much a crappy thermometer can result in the destruction of the fermentability of your wort. On a single infusion mash, if you have gone above 70 C, as Josh said, you can start to run into real problems.

Get as many thermometers as you can from friends etc and test them at around 66C. You'll often hear advice on how you can check a thermometer by checking it's freezing and boiling point temperature. This is not correct. You need to calibrate it at the temp you are measuring. From memory, the post I linked above proves this.

If your thermometer was okay at mash tempo, the only other thing I can think of quickly is that you may have diluted after the boil with very chlorinated water. I really thingk the thermometer is the firs thing to check though.

Oops! One more question. Are these your first two brews? If so, we'l need to ask more questions after the above are explored.
Last edited by PistolPatch on 05 May 2014, 21:11, edited 1 time in total.
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Post #5 made 3 years ago
Are you using a hydrometer or refractometer to determine FG? A refractometer will not give an accurate reading once alcohol is present. There are online calculators to help with refractometer FG readings, but I haven't used any and don't know which one works best.

Also, you should be pulling your yeast out of the fridge so that you don't shock it with temperature change. I pull dry yeast out of the fridge as I'm bringing the wort up to a boil.
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Post #6 made 3 years ago
Wow, lots of answers!

joshua, BobBrews, PistolPatch: I am stiring during the mashes and the temp did not go over 70C, nevertheless I will check the thermometer

PistolPatch: Yes, those are my first two brews

JackRussel: I am using a refractometer ATC, but I haven't heard about this issue so far and I think you have found the problem! Googling I've found a lot of good stuff, especially those links (sharing here):
http://seanterrill.com/2011/04/07/refra ... g-results/

I will definitely measure my wort correction factor before brewing my next batch. This was probably the reason why I was getting a 4,0% ABV that tasted like a 6,0% (the expected ABV) HAHAHAHAH So I probably have achieved the right FG and was thinking the opposite...time to bottle!

Thanks for the answers guys! As a novice in this world, having somewhere that I could ask and get freaking fast replies makes the learning process pretty easier.

Cheers from Brazil!

Post #7 made 3 years ago
Glad to hear that your gravity may have been fine after all. Did you see the comment on the yeast? Ideally you would pull the yeast out of the fridge at either the beginning of the mash or after mashout. Boil enough water to leave you with 120ml for a single package or 240ml for 2 packs of yeast. Allow this boiled water to cool to roughly 20-25c. Pitch your yeast into this water around 30 mins before you pitch in into your wort. Here is some info from the manufacturer: http://www.fermentis.com/brewing/homebr ... uct-range/

In Portuguese even: http://www.fermentis.com/wp-content/upl ... S05_PT.pdf
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