Scotch Ale Cold Crash

[hafmpty]

Just brewed Brewing Classic Styles Scotch Ale (McZainasheff's Wee). The beer started at 1.099 at 60F on Labor Day (9/2). I managed the temps and kept it at 60F for day 1 & 2. I increased the temp to 62F on day 3 & 4 and then 64F on day 5 & 6.

I checked the final gravity today (9/7). Target FG is 1.027 actual FG is 1.027. So it's where it's supposed to be. I used 2 packs of Wyeast 1728 Scottish Ale with a 4L starter. Attenuation for this yeast is between 69%-73%. Right now I'm at 71.3% attenuation.

I know some people say check the gravity over a three days to make sure it's done, but with this beer, it's at the target FG and I'd like it to really clost to that number (if not right on that number). I will be kegging this beer and any bottling I do will be from the keg.

I don't think it's going to drop much if at all anymore, but I'm wondering...

Should I
1. Let the beer sit another few days to allow the yeast to "clean it up" before crash cooling it to 40F?

OR

2. Go ahead and cool it and lock the FG in at 1.027?

 

[BigFloyd]

I vote number 1.

Even during a normal, temp-controlled ferment the yeast will produce some by-products other than CO2 and ethanol. After the fermentables are consumed and FG is reached, the yeast will eat a good portion of those by-products if you give them a few days.

I also don't think it's a good idea to try and "lock-in" a certain FG, even if it's the target number in the recipe and the beer is going into a keg. Depending on your mash temp, it may or may not be truly finished at that gravity.

 

[Oginme]

I'd let it go another couple of days. I let my scotch ale go a few days at constant fg to allow the yeast to clean up and remove some of the byproducts. The high gravity beers are tough on the yeasts and they do need some time to get to where they are going. Especially since it reached the fg quite fast imho. I usually ferment in the mid 60's on my scotch ale and let the yeast work a little more slowly (~ 2 weeks to fg, and then a little beyond before bottling).

 

[hafmpty]

Especially since it reached the fg quite fast imho.

I wasn't too worried about this. The Scotch Ale book by Greg Noonan said that Scotch Ales will usually finish within 7 days, but he also said they can sometimes take longer. I pitched a larger starter because Noonan said to use a pitch rate almost like a lager. That's what I did.

This is my first Scotch Ale so I hope it's good. I was a little worried though despite Greg's words...I guess we'll see.

Anyway, I'm going to let it sit for a few more days right where it's at (64F). I'll let those yeasties do their job. If they keep chewing through it, it's probably not yeast...probably an infection, so that wouldn't be good anyway.

Thanks to both of you.

 

[beowulf]

My opinion would be to wait another week or so at a minimum for a beer that big. Personally, I would have serious reservations about calling it done after 6 days but that's just me. I would not make the assumption that just because you've reached the target FG that the yeast will magically be done. At a minimum, I would say take some hydrometer readings for a few days to make sure it has stabilized before making the assumption that it's done. I'm not sure that cooling it before the yeast is completely finished will necessarily "lock the FG" where you want it, especially if it ever warms up down the road.

 

[hafmpty]

My opinion would be to wait another week or so at a minimum for a beer that big.

This is only my second big beer. My normal routine is to let my beers sit in primary for 3 weeks and then crash cool for 1 week. I think I'm just going to stick with the normal routine. I definitely want to give the yeast a chance to do their clean-up work and what not. You make good points.

My thought is if it's infected (which I have no reason to think it is) it's going to continue to ferment and I'll end up dumping it. But with the yeast's attenuation only as high as ~73% my calculations say it might drop maybe another point/point and a half. Probably not much more. That's not going to make a huge difference in the body and overall flavor. But pulling it out too soon or cooling it too soon might if the yeast haven't had a chance to eat some of their own byproducts.

Thanks.

 

[GuldTuborg]

Those numbers Wyeast publishes are garbage. Ignore all that and give the beer time to finish. If anything, drop the temp just a couple degrees a day to start the cold conditioning while giving the yeast time to adjust & finish. You'll make a better beer this way.

 

[hafmpty]

Those numbers Wyeast publishes are garbage.

Why would a reputable yeast manufacturing company post numbers that are "garbage"? That doesn't make any sense either professionally or financially. What's your reason for saying this?

 

[GuldTuborg]

Wyeast has said so themselves. I forget where I read it, but I could probably find it again with a bit of searching.

Point is, you can't really use the numbers to predict FG in your beer. They're really only useful to get a feel for the typical attenuation differences between strains, given identical conditions.

 

[hafmpty]

Wyeast has said so themselves. I forget where I read it, but I could probably find it again with a bit of searching.

If you could find it that would be great. I have not heard this before but that has more to do with my inexperience than anything else. If you could point me in the direction of the article that might be helpful in the future too.

BTW what is the advantage of the slow chill you mention vs just leaving it at its current temp for the next week or so and then just cooling it quickly?

 

[GuldTuborg]

I'll see if I can track it down tomorrow. It may have been in an interview I heard, I think, so I don't know if I'll be successful. I'll give it a shot, though. I do remember what was stated, more exactly, was this: Most all ale strains (with very few exceptions) attenuate within 1-2% of each other. Wort composition and fermentation schedule play a far larger role in actual AA than strain selection. The published numbers are old, often misleading, and they intend to update how they inform people about this facet of their product, but it's a lot of work. Plus, they feel they have to publish something, as people expect it, so they're not going to stop publishing them until they have something else in place.

As for the slow cooling, with a cold friendly strain like this one, it gives the yeast time to finish up reasonably well while you get it to drop out. If the yeast is still working when you drop the temp quickly, you could be left with too much fermentation byproducts than you'd like.

 

[hafmpty]

I'll see if I can track it down tomorrow. It may have been in an interview I heard, I think, so I don't know if I'll be successful. I'll give it a shot, though. I do remember what was stated, more exactly, was this: Most all ale strains (with very few exceptions) attenuate within 1-2% of each other. Wort composition and fermentation schedule play a far larger role in actual AA than strain selection. The published numbers are old, often misleading, and they intend to update how they inform people about this facet of their product, but it's a lot of work. Plus, they feel they have to publish something, as people expect it, so they're not going to stop publishing them until they have something else in place.

As for the slow cooling, with a cold friendly strain like this one, it gives the yeast time to finish up reasonably well while you get it to drop out. If the yeast is still working when you drop the temp quickly, you could be left with too much fermentation byproducts than you'd like.

Thanks for your input on this. Very helpful. I hope you can find that interview and/or article.