Carafa Special 3 and FG

[danwlx]

Hi all

Brewed the below a couple of weeks ago;

Maris Pale - 80%
Crystal - 8%
Torrified Wheat - 7%
Carafa Special 3 - 5%

OG was 1.056 and I used WLP007, having made a 1.5l starter.

After a couple of weeks the gravity is at 1.018 which is a fair bit lower than the usual attenuation for this yeast, even after plenty of rousing.

Could the level of Carafa Special 3 used leave that amount of unfermentables in the wort?

Thanks for any help.

[Lars]

I brewed a wheat porter with 3.5% carafa special3 and hit FG of 1.014 using wlp004, doubt if it's that

[jimp2003]

I doubt its down to the carafa special 3. What temp was the mash at?

[danwlx]

Mashed at 66.5c. I'm at a loss as to the reason why I can't get the gravity any lower then. Should I worry about bottling if this is the FG?

[jmc]

If you're worried about bottling you could always add a reliable low attenuating yeast to finish off any fermentable sugars. Probably one with not much character of its own so it won't affect taste eg Nottingham. Make a starter first to give it a chance. Good luck.

[mark4newman]

Hi

WLP007, is my go to strain, I would normally expect an attenuation of about 75% to 80%.

Yours is a 68%, which does seem oddly low. I can think of why it has stopped so soon, I haven't ever had any problems with it, it is normally pitched and then it is at FG in three days. I am presuming that you oxygenate the wort, and kept it at the right temp (19C is the temp I use)

Can you recheck your original gravity? I always take a small sample of my original wort, and keep it in the fridge , just to double check that I didn't get the original reading slightly wrong. It has been know.

Also it is worth doing a forced ferment. I normally just put some of the dregs for the boil into the flask where the yeast was (normally enough left aroud the sides etc_, and then turn on the stir bar. Within about 36 hours this will then have finished fermenting, and you will know the FG you can expect.

As for bottling, it is a bit hard to advise.

For me, I bottle with swing tops, and always do one bottle in a plastic sparking water bottle. That way if they are overcarbonating, I will know from opening the plastic bottle (and this acts as a check that they are carbonating, as it expands), then I an flip the lids and then reclose them.

If you don't have flip tops, then I would fill spring water bottle, and not prime it. Leave it in a warm place for two weeks and see what has happened. Sometimes, the yeast will just start up again for nothing better than it didn't like the view where it was.

[danwlx]

Thanks for the replies!

It's been fermented at a steady 20.5.C for two weeks so no issues there.

I have no nottingham in stick but do have danstar and US05. Would either if these be suitable?

Many thanks for the forced ferment tip, I have no stir bar but assume that occasional shaking would achieve a similar result?

[mark4newman]

Hi

Two weeks @ 20.5C

Sounds like you seriously underpitched (or not enough 02), which might be the reason it has gone to sleep.

This a good calc for pitching rates.

http://yeastcalc.com/

Also, I presume if you force ferment, without a stir bar, then you will need to use alot more yeast. Yeast works better with a stir bar, as it forces off the C02, and aerates the wort. Also the yeast works better in suspension/

Just plug some numbers into the wort calc, and you will see how much yeast likes to being spun round!

[jmc]

Thanks for the replies!

It's been fermented at a steady 20.5.C for two weeks so no issues there.

I have no nottingham in stick but do have danstar and US05. Would either if these be suitable?

Many thanks for the forced ferment tip, I have no stir bar but assume that occasional shaking would achieve a similar result?

US05 = WLP001 is a reliable worker and normally attenuates well. I'd make a starter up with this and when going well add to your main brew.
Only downside IMHO is that US05 takes a while to settle and is a bit dusty.

Once you add it you might want to up the temp a little to 22C if you can to help it finish.
** Edit typo **

[danwlx]

Another quick question, if I try to lower the gravity by pitching more yeast, will this compromise the beer seriously? Having had a taste of the wort its tasting pretty good.

Also, I'm assuming that most of the O2 in the wort had now been used by the first yeast, will the second yeast not struggle in this environment?

[jmc]

Another quick question, if I try to lower the gravity by pitching more yeast, will this compromise the beer seriously? Having had a taste of the wort its tasting pretty good.

Also, I'm assuming that most of the O2 in the wort had now been used by the first yeast, will the second yeast not struggle in this environment?

US05 doesn't add a lot of flavour, that's one of the reasons its used for hoppy beers.

Lack of O2 is not ideal, but you're not after yeast growth (where O2 needed), you just want the added yeast to finish off the small amount of any fermentables left.

Get the starter going well before adding and it should be able to cope.

[danwlx]

Just an update on this. I pitched US05 onto this (after getting it up and running in a 1L starter) last Wednesday. There hasn't been much sign of activity and the FG hasn't shifted.

I'm going to assume this is good to bottle at the weekend. The beer from the sample jar tasted good, just a bit odd that the FG is so high.

[weiht]

Pitching a US05 isnt gonna do much. Rousing also may not be as effective as many think actually. U may be best trying to raise the temperature to 22c (Have u seen how they clump together in the vial!!!) with a rouse to get the yeast going again, raising temperature gets the yeast excited again and may help u finish with a few pts lower but I wont expect it to go 1014.

What u may do is take a sample enough for a hydrometer reading and put it somewhere warm in the mid-high 20s for 2 or 3 days before taking a reading, if it drops lower than u know what the potential FG should be.

Possibly underpitched or the yeast is famous for dropping out early, so raise the temperature a few degrees will allow it to finish and clean up. Just stay below 24c. I shld expect it to drop maybe to 1016. U also mashed at 66.5c and have about 13% of unfermentables in the recipe, so u may get 70-73% attenuation.

Gd Luck