Should I agitate the bucket before diacetyl rest? (and a few other questions)

[Yirg]

I'm brewing my first two lagers in parallel, doing pale and dark partial mash versions. There's a difference of one day between the two, and the first brew has already stopped fermenting, or is very close to it. I only have one fridge (a wine fridge), so if I raise the temperature for diacetyl rest it will affect both buckets. A few questions:

- Should I agitate the bucket before diacetyl rest to encourage further fermentation?
- Should I wait for the second bucket to show no activity in the airlock to start the diacetyl rest?
- I'm brewing in 1 gallon buckets so I try to reduce the number of density samples I take (to increase yield). So far I only sampled once, right after adding the yeast. Would it be sufficient to only sample once more, before moving to secondary for lagering? BTW, I already ordered a refractometer, but currently I only have a hydrometer.
- The first brew (the pale lager) was somewhat scorched due to lack of stirring when adding the malt (500g dried extra light malt extract and 150g light LME). The resulting wort seems much darker than I expected, not sure if it's because of the scorching. The taste doesn't seem bad (though I only have a few ale brews under my belt - 2 IPA's, a Stout and a Chimay blue clone). I also didn't aerate it enough, so fermentation took more than a day to start. How likely is it to end as a bad batch?

Thanks in advance!

 

[hercher]

Before your questions can be answered, you need to take gravity readings. How do you know that the first brew has stopped fermenting without that.

Don't worry about not having a refractometer. You don't need one, and at this point it wouldn't do you much good anyway because alcohol skews the reading. Your hydrometer is your best friend in the brewery right now.

I'm not a big fan of agitating the fermenter. If you do, do it very gently so as not to introduce any oxygen into your beer. The point is to gently rouse the yeast back into suspension.

Yes, I would wait until both beers have reached finishing gravity before doing your diacetyl rest, though if you are a day early on one, it won't be a big deal.

 

[Yirg]

Before your questions can be answered, you need to take gravity readings. How do you know that the first brew has stopped fermenting without that.

Thanks for replying. I obviously plan to take additional gravity readings, but I'm just trying to avoid them when there's still good chance of fermentation. I just don't want to reduce the yield of an already very small batch. Would one reading a day after I start diacetyl rest and another at the end be sufficient to show no change, and hence stopped fermentation?

Don't worry about not having a refractometer. You don't need one, and at this point it wouldn't do you much good anyway because alcohol skews the reading. Your hydrometer is your best friend in the brewery right now.

If only there was a hydrometer that required less liquid to show its reading...

As for the refractometer, are two readings (taken a day apart) that show the same result enough no prove stopped fermentation? In this case does the skewed value due to the alcohol have any significance? As long as I take the final reading using a hydrometer I should be able to tell what the FG was, no?

I'm not a big fan of agitating the fermenter. If you do, do it very gently so as not to introduce any oxygen into your beer. The point is to gently rouse the yeast back into suspension.

Noted.

Yes, I would wait until both beers have reached finishing gravity before doing your diacetyl rest, though if you are a day early on one, it won't be a big deal.

Isn't lack of activity in the airlock for a whole day enough to tell that it's time for diacetyl rest? I'd assume that at this stage whatever fermentation is left to be done will be induced by the higher temperature and will shortly be over.

 

[WoodlandBrew]

I would start the d-rest. Most of the flavor has already developed and you want the yeast a little active to do the clean up work.

 

[JimRausch]

Traditionally the time for a D-rest is when 75% of the fermentation is complete, when the yeast are still active. So, a Hydrometer reading then is probably more important than a reading later.
However, if readings are limited because you don't want to waste the beer, then after 1 week in primary at(woops, I don't see a temp. That's important) should be a decent enough guess as to when it's time to raise temps for a D-rest.
Other Qs:
I don't worry about introducing O2 by swirling. After all, you're not going crazy there,right? And there is a protective layer of CO2.I pretty much always give my buckets a swirl after a week or so when I start to raise temps, just to keep the yeasties interested.
If the potentially scorched sample tastes OK, it's probably fine. Scorching is usually apparent right away(yuk).
Good luck with these batches!

 

[JimRausch]

Traditionally the time for a D-rest is when 75% of the fermentation is complete, when the yeast are still active. So, a Hydrometer reading then is probably more important than a reading later.
However, if readings are limited because you don't want to waste the beer, then after 1 week in primary at(woops, I don't see a temp. That's important) should be a decent enough guess as to when it's time to raise temps for a D-rest.
Other Qs:
I don't worry about introducing O2 by swirling. After all, you're not going crazy there,right? And there is a protective layer of CO2.I pretty much always give my buckets a swirl after a week or so when I start to raise temps, just to keep the yeasties interested.
If the potentially scorched sample tastes OK, it's probably fine. Scorching is usually apparent right away(yuk).
Good luck with these batches!

 

[Yirg]

I would start the d-rest. Most of the flavor has already developed and you want the yeast a little active to do the clean up work.

I agitated the pale lager bucket a bit and now there's activity again, and the dark lager bucket is still quite active even without any agitation. Is there any risk in waiting until the latter is also less active?

Traditionally the time for a D-rest is when 75% of the fermentation is complete, when the yeast are still active. So, a Hydrometer reading then is probably more important than a reading later.
However, if readings are limited because you don't want to waste the beer, then after 1 week in primary at(woops, I don't see a temp. That's important) should be a decent enough guess as to when it's time to raise temps for a D-rest.

The temperature is between 12C at the bottom of the fridge and 15C at the top. This is supposed to be the optimum according to the data sheet (PDF file) of the yeast I'm using - Fermentis Saflager S-23.

Earlier the temperature was between 14-17C, probably because of the more active fermentation.

In any case I'm not close to a week and the fermentation has already slowed down considerably. I cooked the pale lager on Sep 1 (four days ago) and the dark lager the next day. Could it be that the smaller batch (1 gallon) accelerates the fermentation stage?

I don't worry about introducing O2 by swirling. After all, you're not going crazy there,right? And there is a protective layer of CO2.I pretty much always give my buckets a swirl after a week or so when I start to raise temps, just to keep the yeasties interested.

This makes a lot of sense and indeed a gentle swirl did restart fermentation.

Thanks for all the replies!

 

[ballsy]

I agitated the pale lager bucket a bit and now there's activity again, and the dark lager bucket is still quite active even without any agitation. Is there any risk in waiting until the latter is also less active?



The temperature is between 12C at the bottom of the fridge and 15C at the top. This is supposed to be the optimum according to the data sheet (PDF file) of the yeast I'm using - Fermentis Saflager S-23.

Earlier the temperature was between 14-17C, probably because of the more active fermentation.

In any case I'm not close to a week and the fermentation has already slowed down considerably. I cooked the pale lager on Sep 1 (four days ago) and the dark lager the next day. Could it be that the smaller batch (1 gallon) accelerates the fermentation stage?



This makes a lot of sense and indeed a gentle swirl did restart fermentation.

Thanks for all the replies!

Won't swirling the bucket risk the "bitter" krausen foam which adheres to the sides of the bucket to be re-introduced to the beer though?? Any risk of off flavors from this?

 

[Ster]

As far as taking gravity readings....

I use a spray bottle to spray starsan solution on the hydrometer and drop it right into the fermentation bucket.