Re Pitching Yeast

Sounds like a near perfect time frame for an ale fermentation. Only way to know though is by taking gravity readings. If I brewed an ale on the 13th, I would expect it to be done fermenting on the 16th or maybe the 17th.

 

How long do you expect active (visible) fermentation to last? A month? RDWHAHB.

 

What you describe is perfectly normal. Here's what is happening in your fermentor:



The production of CO2 is slowing which is normal, but other more subtle fermentation reactions are taking place. If you pitched at the proper temperature, now is the time to slowly raise it 3-5 degrees. Around the two week point consider taking a gravity reading . . . wait about 3 days and take another reading. If they are the same you are finished. Do not be in a hurry to bottle, three weeks of primary fermentation can only help.

If you're really interested, here are the details on what's happening. It's a long read, but understanding this makes your beer taste better. You will see RDWHAHB a lot . . . good to learn and heed.

 

I used to believe this theory that three weeks in primary helped. There are detrimental effects however. Most of the time, if you have pitched enough yeast and aerated your wort, you really only need more like 3 days of conditioning time. At that point, if you want to continue to age the beer warm, you should really consider transferring to a secondary (particularly if you want to reuse the yeast in the fermenter). Other wise, cold crashing for a week is usually better for the beer than continued warm aging on the yeast.

 

Would it be highjacking this thread if I asked another yeast question? I'm going to... then ask for forgiveness later. Been brewing for a few years and have not reused a cake so I have some questions. If I want to reuse yeast how long can I keep it refrigerated, or do I need to reuse it right away. And if I can refrigerate it, how much do I keep?

 

If you had a clean, healthy fermentation which results in low levels of fermentation by-products (e.g., low levels of diacetyl, low levels of acetaldehyde, etc.) there is no need for bulk conditioning. Having stated that, I do not think there are any negative consequences if a homebrewer wishes to bulk condition after primary fermentation is complete. What do you think are the “detrimental effects” if a homebrewer chooses to bulk condition after primary fermentation is complete?

Cheers!

 

If I understand your question, you will want to "wash" your yeast cake, here's a good tutorial. Manufacturers recommend keeping only a couple of weeks, I regularly keep a couple of months, others post they keep six+ months. It should be refrigerated at 35'ish, but I keep mine around 40. If all is fresh and healthy when you start, I estimate 2 billion cells/ml, then reduce it 21% a month. Some of this is a WAG . . . but you have to start somewhere.

And yes, I think we are both guilty of a thread-jacking misdemeanor.

 

My guess is autolysis. There should be an asterisk every time someone recommends the howtobrew website. Palmer himself has since changed his stance on transferring beer off the yeast in favor of waiting longer. I don't own a newer copy but there are probably other discrepancies as well.

 

At the scale/dimensions of homebrewing autolysis takes many months; a week or two of bulk conditioning will result in zero signs of autolysis.

Cheers!

 

Actually, that is not entirely true. Yeast will die pretty rapidly following fermentation. A bucket with co2 and ethanol is not a very friendly environment for yeast when there are no more nutrients to consume. I frequently look at my small batch yeast under a microscope at work and I have found that to be the case. The autolysis is not showing up in the taste, but as the yeast dies, the pH of the beer rises. The higher pH will affect bottled beers that you might want to age, leading to faster spoiling. This is not a concern for most brewers, but it is not wise to tell someone to leave beer on a yeast cake for three weeks without describing the potential risks as well. That said, if the beer is being drank fresh, I would just go ahead and cold crash it, save the yeast, and reuse. I also wouldn't reuse yeast that has sat in a fermenter for three weeks at fermentation temps... Even if the viability is still ok (which it probably wouldn't be), the vitality will be low.

 

Thanks! and sorry for thread-jack.

 

“The higher pH will affect bottled beers that you might want to age, leading to faster spoiling.” This is the first time I have heard of beer pH rising with time in the primary. Have you measured this (or have white papers which document this)?

I personally do not understand the correlation of higher pH equating to faster spoiling. My concern with beer ‘aging’ is staling; which is predominantly oxidation processes. Can you please further explain why a higher pH results in spoiling (and what does beer spoiling exactly mean)?

Cheers!

 

As far as beer spoiling goes, for most people that concern is minor. That said, no one in the world brews sterile beer. At higher pH levels! more beer spoiling organisms can survive. It might take years for a contamination to be apparent, but I have tasted 8-9 year old home brew that took all that time for a contamination to become apparent in the flavor. Lower pH will delay or possibly prevent this.

In addition, from a flavor standpoint, lower pH does effect the way beer is tasted. In particular with bitter beers. Most of us know that higher pH levels in your boil increase hop utilization. However, at higher pH the ability to discern the different hop flavors is lessened. In many cases, beers with lower pH will taste mor3 bitter than beers with higher pH even though the higher pH boil resulted in better hop utilization. The theory is that this has to do with our saliva being near a 7.0 pH, the greater difference in pH level between saliva and beer leads to a better ability to taste the beer.

All that said, if I'm home brewing a pale ale or an IPA, I don't worry too much about it and I transfer off yeast whenever I have time. If I am brewing a lighter beer like a cream ale with more delicate flavors, I will pay more attention to pH and time of beer on yeast cakes. The same is true for beers that I plan to age for 10 or more years.

 

The [low] pH is one of the things in beer that resists spoilage. Others are alcohol, and iso-alpha acids from hops. The acidity helps ward off spoilage bacteria because its not a good environment for them. So higher pH (less acidic)=> faster spoilage. (all things being equal)

 

Missed the edit period but thought I should add:

Oxidized beer is like stale bread. Still bread, just not as good. Spoiled beer is like rotten bread. Don't eat it.

Because of the built in defenses in beer, its not very likely your beer will spoil. On the other hand, every beer eventually stales (oxidizes).

Also, 3 weeks is not too long to sit on a yeast cake. I only worry, and usually for no reason, after at least 4 weeks.

 

“Because of the built in defenses in beer, its not very likely your beer will spoil.” So, should we be concerned about ‘higher’ beer pH or is it just a red herring?

Cheers!

 

People have had batches ruined by bacterial and wild yeast infections. Given that higher pH allows faster growth of spoilage organisms, I'd say it's more than a red herring. But there are a lot of factors. some are...
- what kind of initial inoculation rate of the spoilage organisms?
- post fermentation yeast health (which was influenced by pitch rates, oxygenation, nutrients, etc.), which will partially determine autolysis rates. Yeast cells are bursting all the time...it's just a question of how fast.
- temperature of beer (higher temps drive faster autolysis and also faster reproduction of spoilage organisms (both from the higher temps and from the higher pH))

Get the right combination of factors, and sadness will ensue. But there's enough direct experience out there for us to know that a few weeks in the primary won't usually have seriously detrimental effects.

 

The longer you wait...the greater the need to make a starter.
IMO...you can pitch it...as is...within two weeks. After that...probably more better to make a starter.

I keep as much washed yeast as I can harvest...then pitch as much as I need.

 

The problem I have is that people continue to say that beer benefits from sitting on the yeast. That is simply not true... Unless you are using poor practices before pitching. "Brewers make wort. Yeast makes beer." Take care of your yeast and you will be rewarded.