The Dreaded 1.020 FG...

[Vegetarisk]

Please forgive me if this question has been asked before. Why is that extract kit recipes tend to get stuck a 1.020 FG? I've brewed 3 extract kits and the FG have stopped dropping at 1.020.

More recently I brewed an partial mash-extract recipe and have had the same results. This recipe was based off an extract kit, however I used all DME in place of any LME. I realize the outlier is the fact this one was partial mash, but fermentation seems to be stalled at 1.020 after 2.5 weeks of fermentation. FG was right on target at 1.062 using BRY-97, but my target FG is 1.017-1.012.

Why does this seem to happen with extract recipes? Older ingredients?

 

[Peyope]

I can't comment about the extract aspect, but there could be other factors such as temp, how much oxygen you add, and the amount of yeast you pitch.

If you're already aware of this, ignore this comment and wait for an extract brewer to chim in.

 

[Yooper]

Some brands of extracts are more fermentable than others. When I started brewing, there was one brand called Laaglander or something like that was as little as 55% fermentable! I think most now are over 65%, but it does depend on the brand.

I had many extract batches stop at 1.020, probably several dozen, and aside from certain brands of extract I never really had a good reason for the reason they stopped there. I did oxygenation, yeast starters, temperature control, etc, and sometimes I still ended at 1.020.

 

[LAHammer]

I've had several brews that wouldn't pass 1.020 but still turned out nice. Missing OG by 3 isn't a killer.

With extract, we are at the mercy of the manufacturer as to the fermentability of the sugars. However, I mostly credit it to my technique and impatience. Sometimes I can't wait another week for 2 or 3 points - I'm ready to keg and enjoy!

Don't fret over a few points. Just work on the partial mash technique and you'll be drinking great beer. I love working with extract and I primarily use DME.

 

[flars]

Are you using a refractometer to measure SG?

 

[rodwha]

I use Briess mostly and have never had this problem in over 40 batches.

I did have 2 that got stuck but this was due to over cooling as SWMBO had to keep tabs on my beer while I was in the hospital, and failed.

 

[Vegetarisk]

Are you using a refractometer to measure SG?

Hydrometer

I used Briess as well and fermented in a swamp cooler at 70F. I actually pitched at around 75 and fermentation was pretty vigorous. I raised the temp a few degrees and will check the sg in a couple of days to see if that helps before bottling.

 

[McGarnigle]

Sometimes there's a redundancy issue. Extract may already contain some specialty grains, but then people add more on top.

Also, inexperienced brewers often have problems with yeast pitching, etc., and inexperienced brewers typically use extract. So we're confusing causation and correlation. (ADD: which isn't to say this explains everything.)

 

[Calder]

What yeast are you using?

I did have 2 that got stuck but this was due to over cooling as SWMBO had to keep tabs on my beer while I was in the hospital, and failed.

I hope she doesn't read this site or you are in trouble.

 

[ArkotRamathorn]

I find that doing some sugar additions tends to help drive down my FGs.

I know most recipes don't leave a lot of room for additional gravity but I think it's a little like adding rocket fuel to your muscle car. But due to the extract you are using may or may not be more/less fermentable than other extracts, it is worth the risk looking at primary fermentation additions of simple sugars.

If I am looking at a recipe less than 1.050, I would do a tiny addtions of invert sugar solution syrup in the range of less than 4 oz of sugar. If the beer is going to be between 1.060 and 1.075 I would look at 6-12oz additions. Higher gravity than that, I look at splitting the additions out and adding up to 1.5lbs of sugar.

Either way if it is split out nicely I notice that it gives a big rocket boost to the yeast. Even a lower attenuation yeast like S04 will go up to 80-85% attenuation. Either way it'll give a boost and it will modify the mouthfeel, final gravity, ABV%, so even in this case if the same beer stays at 1.020 it won't taste or feel like a 1.020 final gravity.

I had a scottish export 80 stall out at 1.030. I tried everything to get it to drop 10 more points. It was driving me crazy, literally everyhing in the book, rousing, sugar additions, warming it up, doing nothings and leaving it next to a heater for 3 weeks and it didnt move. I did a total of 1lb of sugar I inverted. During a homebrew club meeting where we compared scotch ales, SWMBO prefered other member's entries because mine was too dry (when I bottled I double checked the FG and still go 1.030, and my entry definitely still tastes dry to me).

 

[Vegetarisk]

What yeast are you using?

Danstar BRY97, but I've had the same results with US-04 and US-05.

 

[DurtyChemist]

Id say you need more oxygen in your wort before pitching your yeast. I use to dump my wort from pot to bucket about 2 or 4 times until there was so much foam it was at the top of the bucket.

Second thing would possibly be temperatures of fermentation but I don't know how well insulated your fermenting area is in VA at this time of the year.

 

[Vegetarisk]

Id say you need more oxygen in your wort before pitching your yeast. I use to dump my wort from pot to bucket about 2 or 4 times until there was so much foam it was at the top of the bucket.

Second thing would possibly be temperatures of fermentation but I don't know how well insulated your fermenting area is in VA at this time of the year.

I did that 3 times and also strained the wort through a nylon paint strainer. I also stirred the wort for a few mjnutes after that. Im thinking its possible the amount of oxygen absorbed may have been affected by the fact i pulled the wort out of the ice bath at 80F for some reason.

I pitched at about 75F and put the wort into a swamp cooler and had the temp down to 66-68 (according to the fermometer on the side of the bucket) within 24 hours when fermentation kicked off

Is it possible I filtered out some fermentable sugar by straining the wort?

 

[flars]

There may be three may items which resulted in your ferment stalling.

Pitching the yeast warm, then cooling the wort.
Under pitching the yeast, especially if you didn't rehydrate.
Lack of sufficient aeration.

One of these, or even two, may not be a problem, but all three together may have resulted in the stalled ferment.

 

[Queequeg]

Some brands of extracts are more fermentable than others. When I started brewing, there was one brand called Laaglander or something like that was as little as 55% fermentable! I think most now are over 65%, but it does depend on the brand.

I had many extract batches stop at 1.020, probably several dozen, and aside from certain brands of extract I never really had a good reason for the reason they stopped there. I did oxygenation, yeast starters, temperature control, etc, and sometimes I still ended at 1.020.

I think Daniels talks about this and he references a study of extracts on the market. A lot of them have low fermentability