First All Grain - High FG

[wildestripe]

Hi All...

I've been studying today different possible reasons why my first All Grain batch didn't get down to a reasonable FG. I thought I'd post a couple of my ideas to get some feedback before my 2nd attempt and to make sure I understand some concepts correctly.
Background:
1. Added 10lbs Vienna Malt to my strike water that was at 183F and adjusted with room temp water to get it to 160F. This was using BIAB and combined they nearly filled my 5gal pot. Sat for 1hr.
2. Rinsed the grain bag in additional hot water (around 183F) as a sparge step for about 10min, then added that to the main pot. Total volume around 4.8gal with a OG of 1.044
3. Boiled for 1hr with hop additions, then had a real hard time cooling it. Took 4hrs and finally pitched Nottingham yeast at 88F stirring it constantly to try and get the temp down more.
4. Next day fermentation was intense, morso then I ever saw with my extract brews. Lasted about 24hrs.
5. Huge yeast cake at the bottom of the fermenter. 1" or so.
6. Left it in primary fermenter for 14days. Transfered to bottle bucket with 4oz disolved sugar. Took a reading and FG was 1.030.

So my ideas are....

a) Did I mash at too high a temperature and create more "unfermentable" sugars which is why I only went from 1.044 to 1.030?
b) Did I pitch the yeast too hot ? Not sure why they went really well at the start then stopped. Temperature was kept constant at 66-68F.
c) Any other ideas of what could have happened here?

Thanks in advance for any advice anyone can give!

 

[Yooper]

A. Yes, 160 is exceedingly high and would favor alpha amylase. That means a fuller bodied beer with a high FG. But 1.030 is very very high. Can it be that you took the FG after you added the priming sugar, which would also increase the SG?

B. Yes, far too hot. 60 degrees, up to 64 degrees or so, would be far preferable. Yeast love being warm, and fermentation would go very fast (even be explosive) at such a high temperature. Fermentation can be over in less than 24 hours when pitched at such a warm temperature. Nottingham really tastes foul to me when fermented above about 65 degrees, which often means an ambient temperature of 60-62 degrees works best for that strain.

C. The too-warm pitch won't cause a super high FG, just create off flavors. I suspect that that mash started out much higher than 160 in the beginning, and that is the real cause of the issue, since adding 183 degree water to room temperature grain would create a dough in temperature of more like 170 degrees. When I first started, I kept a few ice cubes on hand as well as some boiling water in case I missed the temperature by a large margin. A few degrees won't matter, as long as you're in the 149-158 degree range to start, but more than that does matter.

You'll have those fixed for next time, I'm sure.

 

[wildestripe]

Thanks for the reply Yooper. And yes I see I made another mistake, I took the FG reading *after* the bottle conditioning sugar was added. So hopefully my ABV is a little better than the 1.8% I calculated

 

[doug293cz]

You aren't by any chance using a refractometer to measure your FG are you? Refractometers are greatly affected by the presence of alcohol, so you need to do a correction in order to get a reasonably accurate FG.

Brew on

 

[RustyHorn]

I recently did a brew where I pitched yeast at too high a temperature and it fermented for about 24 hours then stopped. After two weeks I took a reading and it was at 1.022 and stayed at that for a few days. Basically, fermentation had stopped but hadn't finished. I warmed it a little and swirled the bucket and it kicked off again.
Did you try to get the yeast going again?

 

[BalloonGuy]

You aren't by any chance using a refractometer to measure your FG are you? Refractometers are greatly affected by the presence of alcohol, so you need to do a correction in order to get a reasonably accurate FG.

Brew on

Is there a formula that can be used to to correct refractometer readings? I was under the impression that I had to use a hydrometer once alcohol is present.
Thanks in advance.

 

[JohnnyBrewGood]

A. Yes, 160 is exceedingly high and would favor alpha amylase. That means a fuller bodied beer with a high FG.

I start at 160. I have found when I pour in my grains @ 160 I end up right @ 154-152. Isn't that perfect?

I read the OP started 183- added room temp water to reach 160- then added grains? I might be wrong. But I have done the exact same thing when not paying attention while milling and heating.

 

[Onkel_Udo]

I start at 160. I have found when I pour in my grains @ 160 I end up right @ 154-152. Isn't that perfect?

Funny, mine works the same way if my grain is at a normal room temp.

Right now in winter I have to start at 162-163 because the grains is about 14 degrees cooler than normal room temp.

I tend to heat 165 without stirring. Stir for about a minute, drop in the bag, stir again and check temp. If I am on..great. If high, stir a bit more. If I am low I turn on one element and stir like mad with the bad still in until I hit it.

This is not rocket science but each person has to tune both their system and their behavior to get consistent results with their setup.

 

[wildestripe]

Thanks for all the replies guys ... just to answer some questions:

I started at 183, added the grains, then added the water to get it down to 160 as my starting point. I was expecting the temp to drop way faster from 160 through heat loss to get into the right range but basically it didn't hardly drop at all. And at the time, I didn't realize the enzymes can denature if too hot. I was thinking more along the lines that the temperatures were guide-lines not crucial to a chemical reaction

So lesson learned, next batch I'm going to try starting at 160F and see if when I add the grain I get into the low 150s this time.

A little additional info, I was using a C thermometer and running to my computer to calculate the equivalent reading in F as I was trying to get the right temperature. Next batch I'm going to buy an F thermometer so I can stay calmer

@RustyHorn I didn't think of this but now I'm a little worried. Next time if this happens, I'll try the idea of swirling it around and warming it up to see if I can get it going again. I went ahead and bottled it up, hopefully the act of siphoning it around doesn't restart fermentation in my bottles I'm hoping I have a bunch of unfermentables in there and I'll just have tons of flavour

 

[Psylocide]

Here... use this calculator and eliminate some of the guesswork.

http://www.rackers.org/calcs.shtml

 

[RustyHorn]

Next batch I'm going to buy an F thermometer so I can stay calmer

@RustyHorn I didn't think of this but now I'm a little worried. Next time if this happens, I'll try the idea of swirling it around and warming it up to see if I can get it going again. I went ahead and bottled it up, hopefully the act of siphoning it around doesn't restart fermentation in my bottles I'm hoping I have a bunch of unfermentables in there and I'll just have tons of flavour

You don't need a new thermometer! Mash between 64c and 68c; I always mash at 66c. Pitch yeast at the recommended temp on the packet. Usually between 15c - 20c.

 

[RustyHorn]

And put your bottles away from humans!

 

[doug293cz]

Is there a formula that can be used to to correct refractometer readings? I was under the impression that I had to use a hydrometer once alcohol is present.
Thanks in advance.

You can download a spreadsheet here: http://seanterrill.com/2012/01/06/refractometer-calculator/. The site also has info on how to measure your "wort correction factor" which will provide the greatest accuracy with the spreadsheet. If you don't have MS Office (Excel) you can download the free LibreOffice.

While a hydrometer is most accurate for FG readings, many folks report that the spreadsheet above gives them results within 1 gravity point of the hydrometer reading.

Brew on

 

[element533]

Yeah 88 is too hot to pitch. Max is 80 (but still not good), ideal is 65-70 F (for ales, obviously).

That much bottling sugar should only make a 3-point difference, so let's say your actual FG was 1.027, which is still high.

Lower mash temp (142-150 F) produces a more fermentable wort, which equates to lower FG. I haven't done BIAB, but I imagine you probably lose temp throughout the mash, so try targeting 152 F and see what it does. Measure the mash temp! Also, your sparge temp might be too high. Try 170 F.

Make sure you hydrate your yeast properly (if using dry yeast) and are pitching at the right rate (check the date!). Brewing apps can help calculate this. Do a yeast starter a few days ahead of time if necessary to get the requisite number of cells. I think underpitching can still give short-lived activity during the growth phase but low overall attenuation as the yeast get tired.

Also, aerate or oxygenate your wort before you pitch. Get an oxygenation kit with a 0.2 micron airstone and give it a gentle infusion of O2 (wispy clouds of tiny bubbles) for 5-10 min.

Once I started doing all of the above, I usually get first activity within 6 hours and lasting beyond a week.

Lastly, if you need a boost, add dextrose to your recipe. It's good to increase your OG without increasing the FG much, can boost the ABV by 0.5% at least.

 

[wildestripe]

Great ideas there element533 Thank you. I bookmarked this thread and will make a "cheat sheet" for my next brew.

Just an update, I conditioned the bottles for about a week now... no bottle bombs And the taste is just amazing coming to all-grain. The Vienna had the malty taste I was looking for. Definitely low on alcohol, but definitely drinkable.