HELP! Think I many have missed the boat with my D rest.

[RobjF]

Hey guys. Last week I put down my second AG, a Czech pils. Used a stepped up 4l starter of Wyeast Urquell pils 2001. All went well on brew day ended up with just short of my target 30l with 28l of wort with an OG of 1.050.( brew smith est OG 1.046) Pitched at 13c, a little higher than I wanted 10c. Put straight into fermenting fridge per set to 10c. That was on the 27.7.13.
Had the intentions of waiting till it got down to 1.020 and the upping the fridge temp to 20c for D rest till it finished. Then racking and then chilling to 1-3c for 4/6 weeks.
But on the 1.8.13( 5 days on) I checked the sg and it had only dropped to 1.041.
Colour was good taste was good and bubbling away nice.
So three days later,today. I go to the fridge to check and no signs of life. Take and SG and it already down to 1.012 which is where I expected it to finish up.
Seems I may have taken my eye off the ball a little with this one.
What next?
Should I up the temp? Will it even do anything at this point. The SG sample didn't seem to have any off flavours unlike some partial lagers I have done. Which then came good after a D rest.
Or should I just rack and chill for a while.
With my other lagers I have added a small amount to dissolved boiled ldme to my new racking keg to try and purge any O2 from the fermenter as I don't have a bottle of co2. Is that a good idea?
There's a bit there guys but as always any feed back is most appreciated.
Cheers Rob

 

[pk.sax]

You'd have to look it up, I suggest braukaiser.

From what I remember, raising the temp for the last few points is both to have it finish lower and a d-rest. Can't see why the two are linked.

 

[Hippy]

I would definitely raise the temp to 18-20 degrees for 2-3 days regardless of whether you're approaching your terminal gravity as the yeast will still clean up any diacetyl lingering.
If you really want to give the yeast every opportunity to clean up drop from there to 10 degrees for a day, then one degree per day down to 2-3 degrees and hold for 3 days, then down to -2 for 2 days then rack and leave at -2 for another 2 days. There are many other ways to go about it but thats my prefered method.

 

[Bizier]

Hippy speaks the wisdom.

The precursor to diacetyl (alpha-acetolactate) converts to diacetyl for a while after terminal gravity, so you want the yeast awake and looking for extra edibles.

 

[RobjF]

Ok hippy. You seem to know what your talking about and that seems pretty straight forward so I will give it a go. Thanks guys I can stop worrying now.
Cheers Rob

 

[Ross]

RobjF,

Taste the wort, if there's no diacetyl there's nothing to worry about & pointless warming it up. If it has got diaceytl try giving it a warm up, but you have most likely missed the boat.


Cheers Ross

 

[Diesel80]

I have done exactly what hippy has suggested two days ago. About to start crashing down to lager now. Did it before reading this so should be ok by the sounds of it. Beer tasting nice anyway so no real stress just precaution. I brewed warmer than 10 though, 14 deg with S189.

Cheers,
D80

 

[Adr_0]

Isn't the point of a d-rest to produce diacetyl in a controlled environment, then have the yeasties eat it up? The rest itself doesn't get ride of diacetyl, it just prevents/minimises it coming out later down the track. Correct me if I'm wrong.

 

[Goose]

RobjF,

Taste the wort, if there's no diacetyl there's nothing to worry about & pointless warming it up. If it has got diaceytl try giving it a warm up, but you have most likely missed the boat.


Cheers Ross

Sorry Ross, I beg to disagree a little (respectfully of course).

Tasting the wort will not allow you to detect the tasteless diacetyl precursor AAS as mentioned by Bizier above. To detect the AAS you need to run the test described here (also quoted below).

In the past I made this mistake many times, ie tasting the wort, thinking it was free of diacetyl, only to have it appear later during lagering, by which time the yeast is dormant/inactive and even warming cannot coerce the yeast back into action to correctthe problem.

You dont need a diacetyl rest if you cant detect AAS in the wort.

For Brewers Only: The Diacetyl Test​

How do you know if your beer contains an excessive amount of alpha acetolactate (AAL), thus necessitating a diacetyl rest to yield shelf-stable beer? The test is not only easy and accurate, but it requires only some glassware, hot water, and the very sophisticated aroma analyzer found in the middle of your face!

This test is based on the fact that heat will rapidly oxidize the relatively flavorless AAL into butter-like diacetyl. You will need two glasses with covers; aluminum foil works well in this role. You will also need a hot water bath big enough to hold one of the glasses. The water should be heated to 140-160 °F.

Place a sample of your young beer in each glass. Cover and put one in the hot water bath while keeping the other at room temperature. Keep the beer in the water bath for 10-20 minutes.

Cool the hot beer to about the same temperature as the cool sample; a cold water bath can be used to good effect for this. Remove the covers and smell each sample. One of the following conditions will exist:

1. Neither beer smells buttery. This is good! It means that all of the AAL has already been converted to diacetyl and your beer is ready for packaging.

2. The heated sample smells buttery, but the cold one does not. This means that there is excessive AAL still floating around your beer, and you should age it at 60 °F or so for a few days to allow diacetyl to form and then be metabolized by the yeast. Repeat the test to determine the proper time for packaging.

3. Both samples smell like butter. This can be a bad thing. It can be indicative of a pediococcus infection, in which case you should dump the batch and start over, or it can mean that your yeast is incapable of metabolizing diacetyl (see respiratory mutants, above).

It could also mean that your beer is still kind of young and you should try the test again after a few more days of warm aging. Hopefully the diacetyl will fade. Kräusening with fresh yeast may also help, unless the problem is bacterial.