Help with lager fermentation

[RedBarnBrewery]

Hello all.

New to the forum, first post. Been about 15 years since I participated in any forum, apologies if I'm out of touch...

Been home brewing over 13 years now. Started in the kitchen with extract, moved to all grain with a brew-in-a-bag system.

A few months ago, brewed my first lager. Brew day went well. Fermentation seemed to go well, at 55°F. Checked gravity and tasted a sample after about a week. Proceeded to warm up the batch to about 72°F for a diacetyl rest. Let it set for 2 days. Kegged it and tasted it again. Not bad. Lagered at 34°F for about 3 weeks. Served it and it tasted like butter. Was terrible. Left it on tap for about 2 weeks hoping it would change. It did not. Ended up dumping it down the drain.

Brewed an Oktoberfest a few weeks ago. Brew day went well. Fermented at 53°F for 10 days. Tasted a sample and it was good, tasted malty and no butter. Increased temp to 57° for 4 days. Increased again to 65°F for 2 days. Cold crashed for 3 days and kegged it. Took a sample and tasted it. It was terrible. Had no flavor whatsoever, except for butter again. Had an experienced home brewer friend taste it, he detected no butter, but detected sourness. Either way it's terrible. It's currently laggering, hoping it changes.

Long story short, I need some advice for lager fermentation. I'm 0 for 2 currently.

Right now I have a batch of Helles Bock fermenting. It was brewed on a Saturday afternoon. Pitched a 32 oz starter at 60° F, with the chest freezer set to 50°F. Bubbles in the airlock started about 24 hours later (Sunday). I'm typing this on a Tuesday evening, so it's been fermenting about 3 solid days. I need to know what to do next as I don't want to ruin this batch.

Any advice is appreciated. And yes, I will search the forum posts for other threads on lager fermentation... (15 years ago senior forum members would routinely chastise anyone for not searching, hoping that's mellowed out a bit).

Thanks in advance.

 

[couchsending]

What yeast are you using?

Pitch way more yeast than you think possible and pitch it colder.

Fermentation profile depends on your yeast.

 

[RedBarnBrewery]

What yeast are you using?

Pitch way more yeast than you think possible and pitch it colder.

Fermentation profile depends on your yeast.

Thanks for the response. The Helles Bock is fermenting with White Labs WLP833 German Bock Lager Yeast. I made a starter with a 16 oz can of canned wort mixed with 16 oz of filtered water. This was left on a magnetic stir plate for about 16 hours. The wort was chilled to 60°F and the starter pitched. Been bubbling along happily at 50°F. Any advice on what to do next?

I have considered simply kegging it after fermentation stops. I know this is probably not the case, but anecdotally is seems my attempts to do a diacetyl rest is causing diacetyl compounds to form.

 

[9Kegs]

Here is a link to an article written by Dr Chris White:
https://www.whitelabs.com/sites/default/files/Diacetyl_Time_Line.pdf

There are a couple things that stood out in the article that I believe might be factors.

1. Insufficient nutrients (not sure if you added yeast nutrients}

2. There is another way to get the buttery, diacetyl flavor in beer. This is the diacetyl contribution that brewers would rather not talk about. You guessed it ......contamination. Lactic acid bacteria, Pediococcus and Lactobacillus, both produce diacetyl. These bacteria have historically been notorious contaminators of beer, and are called beer spoilers. They are anaerobic, alcohol and heat tolerant. This makes them happy to live in beer. The diacetyl produced by bacteria is far from pleasant, and can taste like sour butter. Small breweries and homebrewers have a difficult time bottling beer in a manner which eliminates lactic acid bacteria. This is one reason why great tasting beer can be bottled, only to develop pressure, sourness, and diacetyl flavors in as little as 8 weeks. What can be done? Sanitize well, bottle carefully and leave some yeast in suspension. This yeast won't kill bacteria, but it will reduce any diacetyl produced from oxidation of acetolactate in the bottle.

 

[Sammy86]

Butter is definitely diacetyl...my guess is you stressed the yeast or possible infection.

Did you use the same equipment? If so, I believe it's time for a good thorough cleaning and changing out beer serving lines.

 

[couchsending]

Thanks for the response. The Helles Bock is fermenting with White Labs WLP833 German Bock Lager Yeast. I made a starter with a 16 oz can of canned wort mixed with 16 oz of filtered water. This was left on a magnetic stir plate for about 16 hours. The wort was chilled to 60°F and the starter pitched. Been bubbling along happily at 50°F. Any advice on what to do next?

I have considered simply kegging it after fermentation stops. I know this is probably not the case, but anecdotally is seems my attempts to do a diacetyl rest is causing diacetyl compounds to form.

Diacetyl compounds aren’t formed by your diacetyl rest, they’re formed long before that.

Is this a 5 gallon batch? If so you’re not pitching close to enough yeast based on the starter procedure you outlined. I would argue you need 2-3x more yeast than what you’re pitching. You can never pitch too much lager yeast, it’s very common to not pitch enough.

I don’t think you have an infection but you never know. The likelihood of you getting diacetyl from pedio is rather low. However you can easily perform a forced diacetyl test to see if there are diacetyl precursors in your beer. Take a small amount of beer that’s done fermenting, put it some sort of sealed container (the white labs vials are perfect), shake it, heat it to say 160, leave for 10, then cool to say 50ish and smell/drink. If there are any diacetyl precursors the heat and oxygen will convert them to diacetyl.

If you do this test and you don’t detect diacetyl then there’s a chance you might have an infection somewhere from your fermentation vessel to the keg. Again I don’t think that’s the case but you never know.

I think you still have diacetyl precursors in your beer and when you’re transfering from fermenter to keg you’re getting oxygen pickup that is converting the precursors into diacetyl.

Pitching insufficient yeast warmer than fermentation temp is a sure fire way to get diacetyl formation. I know there are all these lager “shortcuts” you can find online but pitching a significant amount of yeast at temps colder than your fermentation and fermenting colder will lead to a much cleaner, healthier ferment. You don’t even need to increase the temp past 50 (depending on your yeast). I don’t do diacetyl rests in lager beers and have never had diacetyl in a finished lager.

How are you oxygenating? If you don’t have a way to inject pure o2 into the wort you won’t have enough oxygen, especially for a lager yeast. Ale yeast you can get away with shaking or other tricks, although depends on the strain. Generally not with lager yeast.

Unless you have the ability to make bigger starters, and add pure o2, the likelihood of you getting a successful clean lager fermentation with liquid yeast is not very likely.

If you have a 2L flask the biggest starter you can make is maybe 1.6L. Lager yeast doesn’t generally ferment too vigorously so you can get away with a slightly larger amount of liquid without fear of blow off. I tend to leave lager starters spinning a little longer as they’re usually slower yeasts but that depends on the strain. You’re gonna need at least 2 vials/packets of yeast (WL/Wyeast) that’s pretty fresh in a 1.6L starter to get even close to optimum pitch on 5g of wort. And ideally that’s still not enough.

But if you can’t oxygenate sufficiently dry yeast would be your better option. It’s manufactured with enough sterols that you don’t need to add oxygen. I personally don’t like dry lager yeast that much but others love it. If you’re fermenting in the mid 50s 2-3 packs of 34/70 sprinkled directly into the wort should result in a relatively clean beer. Raising to 60 or mid 60s while you still see fermentation is advisable for this method as well. Not my preferred method but it works for a lot of people.

If you want to use liquid yeast and ferment in the mid 50s I’d recommend that Augustiner strain. It is cleaner at warmer temps than a lot of lager yeast and it’s a very popular strain for craft breweries. The White Labs/Wyeast versions are either hard to find or they kinda suck. Imperial sells it as “Harvest” which is your best bet as a homebrewer.

My personal favorite strain is the Andechs strain which is 835 from WL and Rocky Mtn Lager from wyeast. It’s coming out in October from Wyeast as it’s a “Private Collection” strain for some reason. It’s incredibly fast and clean with low esters and sulphur, and floccs incredibly well. Easiest strain of lager yeast I’ve ever used! Pitch at 46, ferment at 50, raise to 52/54 for the last 1* plato. Usually done in 6/7 days and incredibly clean.

 

[Beermeister32]

Add yeast nutrients, build a 2L starter, pitch at 48F, ferment at 50F, ramp up D-rest to 66F for a week. Transfer to a keg, lager at 34F for 90 days.

 

[jdauria]

As others said, add yeast nutrients. Also, use a good yeast pitch calculator and pitch at least a 1.5 billion cells per ml per degrees plato for lagers. Brewer's Friend yeast calculator allows you to select that rate. For a 1.050 lager, that would be 352 billion cells and would require a 2 liter starter (at 1.040 OG) is yeast was packaged today. 1.060 would need 419 billion, 1.070 484 billion, etc. I brew a lot of lagers and make starters between 1.5-2.0 billion/ml/°Plato and and have never had a diacetyl issue. If you can ferment at 46-48°, even better as supposedly pitching that cold prevents the precursors of diacetyl from even forming, and you don't even need a D-rest.

 

[waldoar15]

Like the others said, big starter.

Unless I'm making a Euro lager I use WLP 940 exclusively and leave them go for 3 weeks @ 50* . They've always been clean without a D rest. I realy like that yeast.

 

[jdonovan]

depending on the age of your packet of WLP833, you might have 'old' yeast. The liquid yeasts have a very poor shelf life, and a packet that is 90 days old could have as little as 1/3 of the yeast viable that left white labs.

You mentioned a 32 oz starter, that is at least 50% undersized, depending on your OG, it could be as much as 3x to small for all the cells you need.

Big starters are cheap insurance for a successful ferment.

 

[RedBarnBrewery]

Hi all and thank you for all the responses. I've spent the last week reading & re-reading all these responses. I do have some questions regarding the yeast starters.

1. How to make a bigger yeast starter? I'd like to continue using the canned wort (16 oz wort + 16 oz water). To make this bigger starter, would I use 2 cans (32 oz wort & 32 oz water) and 2 packs of yeast? Or is it still 1 pack of yeast?

2. What temperature should I make the starter at? I've always just made it in the kitchen, on the stir plate. We keep our house at 75° F all year, therefore my starters are made at roughly 75°.

3. When it comes time to pitch yeast into the wort, a couple of you said to get the wort to 50° first, then pitch. But what temperature should the starter be? Again, mine are around 75° but I could easily cool it down in the fermentation chest freezer.

Some other responses to comments, yes I'm using pure O2 with a diffusion stone. For the most recent batch (Helles Bock) it ran the oxygen for 2 minutes. I've never used yeast nutrients, I'll have to look into that.

Thanks again for the advice. Looking forward to hearing more. Cheers.

 

[jdonovan]

As you double the starter, you will need to double the starting yeast, so yes, 2 packs of yeast.

Room temp 70-75 should be fine.

ideally the yeast, and wort should be close to the same temps.

If it is not obvious, sanitization is very important when making a starter as any other cold side process. Make sure you boil the water and cool it before use. If you don't boil the water in the flask, make sure it gets a starsan rinse before the wort, water, and yeast get added. When using canned wort, starsan on the top of the can before opening, so you don't pull any contamination from the outside of the can into the starter.

some how to links:

here is white labs directions on making/using starters
Homebrew Starter Tips | White Labs

and Jjohn Palmer on starters:
Preparing Yeast and Yeast Starters - How to Brew

 

[couchsending]

Hi all and thank you for all the responses. I've spent the last week reading & re-reading all these responses. I do have some questions regarding the yeast starters.

1. How to make a bigger yeast starter? I'd like to continue using the canned wort (16 oz wort + 16 oz water). To make this bigger starter, would I use 2 cans (32 oz wort & 32 oz water) and 2 packs of yeast? Or is it still 1 pack of yeast?

2. What temperature should I make the starter at? I've always just made it in the kitchen, on the stir plate. We keep our house at 75° F all year, therefore my starters are made at roughly 75°.

3. When it comes time to pitch yeast into the wort, a couple of you said to get the wort to 50° first, then pitch. But what temperature should the starter be? Again, mine are around 75° but I could easily cool it down in the fermentation chest freezer.

Some other responses to comments, yes I'm using pure O2 with a diffusion stone. For the most recent batch (Helles Bock) it ran the oxygen for 2 minutes. I've never used yeast nutrients, I'll have to look into that.

Thanks again for the advice. Looking forward to hearing more. Cheers.

Ideally you’re going to need an even bigger starter than 64oz but it depends. Do you use a pitch rate calculator?

https://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/
You need at least 1.5m/ml/*plato for lagers. I shoot for closer to 2m. That would require a 5L Erlenmeyer flask. Which if you want to make lagers a lot you should have.

75 is fine. You’re trying to grow yeast. It grows better at that temp anyways.

That being said you don’t want to dump 2+ liters of a starter fermented at 75 into a delicate Helles or Pils. Build the starter up, give it 24 hours on the stir plate. I will give it an extra day but prolly not necessary, leave for 36-48 hours in your fridge to hopefully flocc. Pour the beer off the yeast then put it in your fermentation chamber so it’s at a similar temp to what you’re pitching it into.

If you really want to ensure a good fermentation add some cooled first runnings to that yeast in your fermentation chamber on brew day, shake the crap out of it and let it start fermenting at your ferm temp before you add it to the wort.

Try to pitch colder than what you’re going to ferment at and have fermentation be closer to 50 than 55.

 

[VikeMan]

Here is a link to an article written by Dr Chris White:
https://www.whitelabs.com/sites/default/files/Diacetyl_Time_Line.pdf

That's a pretty good article. (I've read it before.) The one thing I don't like is that it implies that diacetyl formation and reduction is a clear cut two step process, i.e. that all of the diacetyl that will be formed is formed, and then it begins to get cleaned up. In reality, the yeast can start cleaning up diacetyl while α-acetolactate in the beer is still being converted to diacetyl.

Diacetyl compounds aren’t formed by your diacetyl rest, they’re formed long before that.

This is usually true, but sometimes there is still some α-acetolactate in the beer that hasn't yet been converted to diacetyl. In this case, the diacetyl rest accelerates the conversion to diacetyl, as well as the cleanup by the yeast. The phenomenon is one big reason that some brewers do forced diacetyl tests.

 

[tennesseean_87]

Another thing I like to do is use lager slurry instead of huge starters. I'll start out by doing a warm fermented session strength (1.035ish) beer with 34/70 dry yeast. Keep it low hopped. Then I'll pitch a measured amount of slurry (use calculator, err on pitching too much) into a lager, and if needed use that cake/slurry for bock or stronger lagers. I do these pretty close together to make sure the yeast isn't too old between steps. Pale session-->Dunkel-->Baltic porter and session-->Penn Porter--> Bock have worked well.

 

[RedBarnBrewery]

Hey gang, thanks again for the responses.

I'm beginning to realize that building a starter of any real size while using those fun little cans of pre-made wort is going to get expensive quickly. Back to DME it is.

I've started playing around with the yeast calculator linked above. I believe I'm figuring it out well enough, but have one question. At the "Starter - Step 1:" section, the Gravity (1.xxx) is filled in at 1.036 by default. The data at the bottom attempts to explain this, but I don't follow. Do I need to adjust this value? If no, great. If yes, how do I determine what the value should be?

Thanks a million for all the responses. This is starting to make sense to me now.

 

[VikeMan]

At the "Starter - Step 1:" section, the Gravity (1.xxx) is filled in at 1.036 by default. The data at the bottom attempts to explain this, but I don't follow. Do I need to adjust this value?

IMO, anywhere between 1.035 and 1.040 is a good gravity for normal starters. I would say there's no reason to change the default.

 

[RedBarnBrewery]

IMO, anywhere between 1.035 and 1.040 is a good gravity for normal starters. I would say there's no reason to change the default.

Thanks. Can you help me understand the "step up" process in the calculator? I'm imagining it involves making a 2L starter with the recommended amount of DME, let it spin for a day or so, then decant the liquid, leaving the yeast and do it all over again? Is this right?

 

[RedBarnBrewery]

Oooooh, I get it now. Increasing the gravity of the starter recipe simply uses more DME. It helps to get the yeast count higher. I see...

 

[VikeMan]

Can you help me understand the "step up" process in the calculator? I'm imagining it involves making a 2L starter with the recommended amount of DME, let it spin for a day or so, then decant the liquid, leaving the yeast and do it all over again? Is this right?

You have described the process well. I would just add a couple things... the first step isn't always 2L. And the second step is generally bigger than the first. And a cold crash is generally in order before before decanting.

 

[RedBarnBrewery]

You have described the process well. I would just add a couple things... the first step isn't always 2L. And the second step is generally bigger than the first. And a cold crash is generally in order before before decanting.

Understood on all points. The calculator and step up process make sense to me now.

On a different note, would it be possible to "save" the poor Helles Bock that I've got going right now? It's been fermenting for about a week and a half. As described above, there was not nearly enough yeast in the 1L starter I made. Could I get another pack of yeast, build up a proper starter, pitch it, and let it ferment for some amount of time? Would this work? Or would I be attempting to ferment a beer that is already a mess?

 

[VikeMan]

It's been fermenting for about a week and a half. As described above, there was not nearly enough yeast in the 1L starter I made.

You definitely under pitched.

Could I get another pack of yeast, build up a proper starter, pitch it, and let it ferment for some amount of time? Would this work? Or would I be attempting to ferment a beer that is already a mess?

Personally, I would let it ride at this point. Low pitch rate doesn't guarantee diacetyl. Several years ago, I brewed a 15 barrel batch of czech pilsner at a comm'l brewery. Well before brew day, I had sent the recipe and process specs to the resident brewer. He said "okay to all." When I arrived on brew day, I found out that he had bought about 1/5 of the yeast count I had specified. The batch (which happened to use a strain kind of known for diacetyl production) turned out pretty good. But fermentation definitely took longer than it should have.

 

[RedBarnBrewery]

You definitely under pitched.



Personally, I would let it ride at this point. Low pitch rate doesn't guarantee diacetyl. Several years ago, I brewed a 15 barrel batch of czech pilsner at a comm'l brewery. Well before brew day, I had sent the recipe and process specs to the resident brewer. He said "okay to all." When I arrived on brew day, I found out that he had bought about 1/5 of the yeast count I had specified. The batch (which happened to use a strain kind of known for diacetyl production) turned out pretty good. But fermentation definitely took longer than it should have.

Thanks for all the help tonight. One last question. I'm also inclined to let it ride. Any guess how long I should leave it fermenting at 50°F before I raise the temp for an attempt at a diacetyl rest? It was brewed on August 29th. I'd guess it started fermenting within a day as I saw bubbles in the airlock.

 

[VikeMan]

Any guess how long I should leave it fermenting at 50°F before I raise the temp for an attempt at a diacetyl rest? It was brewed on August 29th. I'd guess it started fermenting within a day as I saw bubbles in the airlock.

I would start ramping up when the gravity is roughly 4-5 points above your expected FG.

 

[Beermeister32]

On lagers, I usually begin ramping up to a 66F D-rest near the end of fermentation, usually around day 10-12. Timing on the D-rest is not as critical as your flavor profile is already established. I usually ramp up about 5 degrees per day and hold the D-rest for about 5 days to allow it to finish. Some will hold it at 66F for a couple weeks. Others will cold crash at this point.