low attenuation

I just want to say im a big fan of the site, ive been reading forums here for about a year. whenever i have a question this is the first place i go. i just decided to finally sign up because i felt i needed some real brewers advice about a current batch. heres the issue

im not sure if this batch has a stuck fermentation. the OG was 1.082 at about 68-70 degrees. the temp has stayed constant and after 8 days i took a reading of 1.039, and 2 days later 1.037. this only gives me about a 54 % attenuation when i am using a wlp090 which should have around 80% att i think.

i added 1lb of dme and 2 lb of table sugar during boiling in addition to the recipe. im wondering if adding the table sugar before letting the malt ferment first was a mistake, but i thought just 2 lb wouldnt make a difference.

also im wondering if since i had such a OG that maybe im being impatient and just need to wait longer for it to ferment. the fermentation hasnt stopped completely but the airlock bubbles are coming out every 30 sec or so. ive tried shaking up the bucket a couple times and it seems to release more c02 for a few seconds then back to normal.

am i being impatient or is there something i can do to get a better attenuation from this?

That is a higher gravity beer and its only been 10 days.....your only issue is patience....it will be fine. Wait AT LEAST another week before checking it...I would wait 10-11 more days myself.

I primary all my beers (normally) for 3 weeks min.

What temp is the beer fermenting at and what yeast are you using.

Couple questions:
Did you make a starter? 1.080 needs a starter with liquid yeast, or you need to pitch two tubes.

Did you aerate? with a gravity that high you definitely need plenty of o2 for yeast to multiply. I think it is probably too late to aerate again, although Im not sure.

Solutions:
Pitch another tube of wlp090, I would recommend pitching another packet of US-05 or Nottingham, follow the directions on the packet.

Did you do make a yeast starter? You've probably stressed those buggers out if you didn't have the proper pitching rate with that OG. Wait a couple of days and get a grav sample. In the mean time go pick up a vial and some dme and make a starter. If you're still not where you want to be, you can pitch the starter. Some might argue with me, but better to have more than not enough. There's a sticky on how to do one.

Wrote this in another thread... It may only partially apply if you're not brewing Full Extract.

bobbrews said:

Easy fix...

Use Extra Light DME that has ppg ratings close to that of real 2-row, e.g. 37 ppg. I would recommend adding about half of it at flameout.

Be extremely accurate with your recipe; weights, volumes, gravity points contributed, evaporation from the boil, etc. (it may simply be a recipe issue). Employ full volume boils with no top off water whenever possible.

Don't add too much crystal. Keep it below 7% total.

Do substitute 10-13% corn sugar at flameout in place of extract. You'll need about double what is typically seen in all grain recipes. This technique works very well but is better in pale, low to moderate bodied American ales.

Make an appropriate sized yeast starter with high attenuating yeast. Intermittent shaking is good. Stir Starters are better. Yeast nutrient and/or amalyze enzyme may help.

Aerate the wort well before pitching the yeast.

Keep your temperature control down pat for the duration of the yeast starter & primary. For instance, with Cali Ale yeast, consistent ambient air temps in the low 60s should work very well for you (if you don't have a thermometer to measure the wort/beer more accurately).

If all else fails, look into partial mash with some real 2-row in place of extract. Mash the grain around 147 F for an hour.

And lastly, patience. Give your beer 3-4 weeks before bottling.

Click to expand...

thanks for the quick reply. i took a temp this morning of 70, and the yeast is wlp090 san diego. i just got worried because the bubbling has slowed down a lot. i thought it was pretty much done.
do you think after 3 weeks ill be looking at an att of atleast 75?
what about a secondary fermentation. should i leave in in the primary for those 3 weeks or would secondary carboy be an option? id like to free up the bucket for my next batch as it is my only bucket, but not at the cost of ruining this batch.
also i only have 1-1/2 oz bittering hops and 4 1/2 oz of aroma. would this high gravity benefit from a dry hopping? if so at what point?

thanks

i didnt make a starter, i just pitched it right in as soon as the temp was right. and yes i not only aerated, i oxygenated it with a diffusing stone for about 30 sec

I wouldn't take it off the yeast cake and put in secondary.....go ahead and at least pitch another yeast pack....but do not aerate....just dump it in.

The other guys bring up an excellent point I didnt even think about (i must have assumed you did starter even though u didnt mention it) ...you should have done starter from beginning....but I think now if you just pitch another pack/tube you will be ok.

Also, when using liquid yeast.....you should always do a starter even for "normal" OG beers....have you ever done a starter? If not it is easy.....plenty of info on this forum just do a search.

Based on the three reading you have taken my bet is that it finishes on 12/4 with a FG of 1.034. I'm afraid it is looking like your final attenuation will be 58%.

But this is really just a guess based on an exponential fit of the data. It hasn't failed me thus far, but I hope this is the first time.
(like this: http://woodlandbrew.blogspot.com/2012/11/how-to-calculate-fermentation-time.html)

If your readings were off by one each and the right direction then it could be 1.027 on 12/13

LME or a high mash temp would explain the problem.

Just in case it is stuck:

Top ten causes of a stuck fermentation:
http://woodlandbrew.blogspot.com/2012/11/top-ten-reasons-why-your-final-gravity.html

Top ten ways to fix a stuck fermentation:
http://woodlandbrew.blogspot.com/2012/11/top-ten-ways-to-restart-fermentation.html
Only time will tell.

thanks for all of the responses.
so pitching a dry yeast pack will increase attenuation?
i know my readings were correct because i used a refractometer and calibrated before each use. and yes i used lme for the base malt, i havent yet graduated to all grain.
next time i will for sure make a starter, probably for every batch is a good idea. if i wait until the fermentation slows down next time before i add table sugar would it still stress the yeast? or is it just the initial high gravity that stressed them? if i add sugar later in the process should i also add a package of yeast along with it?

my next batch when i free up this bucket is a belgial trippel, a high gravity brew to start with. will a tube of wlp090 with a starter be enough for that? what about if i decided to add sugar to it?

you guys are awesome, i aspire to be like you

Did you compensate for alcohol when using the refractomerer? That would explain it.
Try a hyrometer just to make sure.

You are probably at 1.008, and it will finish at 1.005 on 12/4

Here is a calculator: http://www.northernbrewer.com/refractometer-calculator/

How much yeast did you pitch? My calculations indicate that you would have needed 3 vials without a starter for a 1.080 beer. This could easily be the culprit.

What's the FG of your belgian trippel going to be? 1 vial for a starter may not be enough. 2 definitely will be. If you go with 1 vial, you're going to need a decent sized starter, 3-4L. 2 vials, a 2L starter should suffice.

so if i take my OG 1.082 and convert it to brix, it would be 20.5, and convert my Current gravity of 1.037 to 9.25. if i put it into the calculator it says i have a current gravity of 1.007. if thats the case and i use the formula of
1.082 - 1.007 * 131 i have an abv of 9.825 % ? and that would mean i have attenuation of 91.4 %. is my math right?

im confused how the calculator makes my current gravity much lower

i havent thought ahead to the trippel yet but id hope the FG would be around 1.02 or so
how do you calculate how much yeast you need for the original gravity and the size of the starter?

Update: i just took a reading with a hydrometer and this being day 10 the reading is 1.025. so if i have 3 readings, one from a refractometer, one from a hydrometer, and one from an online calculator, why are they so drastically different? thats attenuation of 69.5% and abv of 7.467%. what do i trust?

You trust your hydrometer reading......your refractometer is not wrong either....just that you have to perform the calculation correctly to get correct SG from brix conversion....once fermentation has begun....which is your case.

The refractometer reading is good for original gravity reading.....BEFORE there is any alcohol in it. Refractometer is calibrated for WATER with no alcohol...its just the way it works.

Once the beer has started to ferment and you have alcohol in there it will throw the refractometer readings off....that is why you need to use the calculator.

So you take a refractometeer reading before fermentation begins.... for your OG....in brix...and do the straightforward conversion to OG....which you said was 1.084

Now that it is 10 days later.....if you use refractometer...you are now getting a reading of a liquid with water and alcohol...so if you convert that to SG with your normal conversion (4 x brix or whatever it is....) you will get an incorrect value.

That is where the calculator comes in.....it will adjust your current refractomter reading based on the OG brix reading and give
you the correct SG...

For the Norther Brewer Calculator link someone posted.....
Under "Brix to Gravity during and after fermentation converter"

Enter "20.5" for Original Brix
Enter whatever your current brix reading is in "Current Brix" and calculator will give you correct SG.

So if your current SG based on hydrometer is 1.025 I suspect your Brix reading with refractometer should be around 12.0

So it looks like you are at around 70% attenuation right now......

ok this is great! i think despite not making a starter its actually going to turn out well. im glad to know that the real problem was the instruments i was using. if i have 70% att and its still slightly bubbling, maybe ill get it to 75 in a couple days. maybe think about secondary soon.
i hope i didnt get any infection opening the lid several times to get readings, but every time i did i used sanitizer on everything, so ill just pray no oxidization.
thanks to everyone for helping me with this problem

so when thebeerist says for a 1.08 SG brew i need a 3 to 4 liter starter, is it really true i am going to add another whole gallon to my wort? does that mean i boil my wort down to 4 gallons to make a 5 gal batch? wouldnt that change the SG?

also while were talking about fermenting, this belgian trippel kit i ordered said estimated OG is around 1.076 ish. lets say hypothetically i made a decent starter, good aeration, even oxygenation. when the ferment starts slowing down, lets say i add 2 lbs of table sugar in a sterile solution. will that shock the yeast or will it start fermenting again? what repercussions would i face?

As long as the alcohol level doesn't go above the level the yeast can take adding sugar after fermentation has slowed is what I would recommend. It will be less stressful on the yeast that way because the osmotic pressure is lower.

You will not add all of the liquid you use to make the starter.

After your starter is complete....you will place it in the fridge and let the yeast settle to the bottom of the flask....give it like a day....then you will have all of the liquid setting above the yeast...then you decant the liquid out (just a fancy word for carefully pouring most of the liquid out without dumping the yeast)...but you have to leave a little liquid to suspend the yeast in. Remember you will need a day for each litre of starter you plan on.....so if doing a 2 litre starter you will need to start this at least 2 days ahead of brew day....I usually give it an extra day in case the yeast is slow to start.

Then you let it warm to room temp.....give it a good swirl to suspend the yeast in the remaining liquid...and pitch them suckers into your brew. SO you may be adding a pint or so of liquid.

Do a search on Fermentation and Yeast forum....you will find all kinds of information...it is quit easy....most important part as usual....sanitation!

Check out this link to Northern Brewer Yeast Starter kit....there is a good video on upper right of screen on how to do a starter

http://www.northernbrewer.com/shop/2000-ml-yeast-starter-kit.html

ok so another question about adding sugar. if i do add a lb or 2 when the fermentation is dying down, how do i adjust the SG or atleast a certain gravity to compare the final gravity to for calculating attenuation and abv?

does that make sense?

mccartney said:

ok so another question about adding sugar. if i do add a lb or 2 when the fermentation is dying down, how do i adjust the SG or atleast a certain gravity to compare the final gravity to for calculating attenuation and abv?

does that make sense?

Click to expand...

Just add it to the OG that you measured.
x = number of pounds added
b = batch size (5 gallons)
43 = pppg for sugar
OG = original gravity that you measured before pitching.

OG + (x * 43 ) / b

So for a 5 gallon batch of 1.080 with two lbs of sugar the new FG is:

80 + (2 * 43) / 5 = 97.2 or a specific gravity of 1.097

Use the same FG that you originally calculated because sugar will ferment out nearly 100%.

should i just pour the sugar in the wort or boil it in some water and cool first? and do i aerate or oxygenate again too?

also i dont remember how fermentable maltose is but im going to guess 75%. would that mean i would adjust the formula for adding malt as
og + (((x*43)/b)*.75) ?

Because you are calculating original gravity the fermentability is not in the OG equation. If you want to calculate a new FG then you can use the 75%. (I pronably muddled that up with my last post) You will want to dissolve the malt in water so that it mixes with the wort better. It can take a long time to finish if the malt is not dissolved.

do not aerate at this point.

so if i add a pound of malt, im sure i would want to use a minimal amount of water to dissolve the malt in to minimize the modified OG. what would the minimum amount of water be for a pound or cup or whatever convenient measure of DME?
What about adding regular sugar. should i dissolve it in water before adding it to the already fermenting brew too or add it dry?
how would dissolving these fermentables affect the calculation of the modified OG not only because of the sugars, but the amount of water too?

Am i asking questions for the way advanced brewer and getting too ahead of myself? im not afraid of a complicated equation knowing all of the variables.

The maximum specific gravity of sucrose is about 1.400, but I forgot what that translates to as a ratio. Although that is hard to achieve. The down side to dumping the sugar in without dissolving it is the time it will take longer to ferment. The sugar will take a long time to go into solution mixed in with the yeast in the bottom of the fermenter. It might take several days to a week to go into solution, but if you are planning on fermenting for a very long time that might be acceptable.

Add the water to your batch volume and the amount of sugar to your OG calculations. For table sugar it would be 46 * (lbs added) / (batch size)

thanks woodland, i know math questions can be hardest, i bet most homebrewers dont even worry about the math involved. what you explained makes sense to me, im glad my questions made sense to you.
tomorrow i brew a belgial trippel, i have a 4L starter about ready i did in 2 2L stages, the sediment at the bottom is an inch thick. its my first yeast starter.

deleted.

for everyone who helped me out with this thread, in case you want to know...
i was worried that the attenuation wasnt where it should be.
i put the brew into a secondary today on the 18th day since there was no more airlock activity. i had a starting gravity of 1.082, FG is 1.015. that is att of 81.7% and ABV of 8.7. not too bad.
but it is very cloudy. i have never had such a cloudy brew go into the secondary. is it because a week ago i shook the bucket while worrying about the low attenuation?
should a couple weeks in secondary fix that? i also have filtering equipment i could use after a couple weeks.