NovaLager starter lag phase and extremely short activity, bitterness

[Brewer #440722]

Hi,

This is a long post but I want to give as much context and detail as possible.

I pitched a three stage starter of NovaLager yeast two days ago into nearly 10 liters of 1.049 wort.

Starter protocol was as follows: 1st stage - 1 liter of 1.040 wort, a pinch of DAP and swirling the flask every now and again. I don’t have a stir plate yet so had to do it manually.

After a day the gravity read close to 1.000, so decanted most of the spent wort and added 1.2 liters of fresh wort of the same gravity. Again, swirling the flask when I could. Third stage was the same, but wort added was a bit more than 1.2 liters. Unfortunately, I wasn’t home for the whole day so I couldn’t agitate the flask, however, at the end of that same day gravity read almost 1.000 and the yeast had flocculated nicely. I crashed the starter in the fridge for two days. Come brew day, I decanted most of the spent wort and allowed the slurry to warm up a bit before pitching.

Initial amount of dry yeast was around 4 grams, which had been kept in the freezer for quite a while, not vacuum sealed. I assumed yeast viabilty was only 20-30%, so that’s why I did a 3 stage starter. According to a few calculators, I should have ended up with over 200 billion cells after the three stages.

Before pitching the yeast slurry, I aerated the wort for a few minutes with an immersion blender. I have never done this before, since I hadn’t known just how important aeration is, especially for lagers.

I put the beer in my cellar at 15C and after more than 48 hours I finally saw vigorous airlock activity. And then I checked it in the evening and… no activity again. It was at most 6 hours of active bubbling. Correction: I noticed bubbling way later than I initially remembered, so at most it was active for 3 to 4 hours.

Naturally, I took a hydrometer sample and it read 1.012, which is just a few points above expected terminal gravity. I realize that airlock activity isn’t the best indicator, however, I have never seen the bubbling stop so soon.

I also tasted the brew and it had this strong bitter taste to it, something I’ve never tasted in my beer before. The only two things that I did differently this time were a small lactic acid addition (3.5ml) and using a starter. Even after adding the acid, mash pH after 20 mins was at 5.77.

(For context, once I got my pH meter, I made a test batch without adjusting water chemistry and using only Pilsen malt. The mash pH was 6.37 at 20 mins and 6.24 at 60 mins. I plan to get my water tested to see the Bicarbonate level. For now I’ll stick to distilled/spring water with clearly declared ion concentrations)

So the questions are: why did airlock activity cease so quickly and what could the harsh bitter aftertaste be coming from? Thanks in advance.

 

[Brewer #440722]

I just now looked at some more info and realised I’m an idiot. For some reason I assumed that the yeast would have a viability of only 20-30% after being kept in the freezer for a year. I most likely massively overpitched. Lesson learned, always do more research than you think you need. Can anybody weigh in with their experiences storing dry yeast in the freezer for extended periods of time after opening? Thanks.

 

[Minbari]

1) starters for dry yeast are unnecessary, they have all the nutrients they need in the pouch.

2). couldn't tell ya why bubbling wasn't what you expected, maybe you have leak and it only bubbled once pressure was high enough? 6 hours of fermentation seems unreasonable

3) bitter is usually from hops. What is your hop schedule?

4) what are measuring ph with? That just seems high. Most of my batches as in the low 5s

 

[Minbari]

I just now looked at some more info and realised I’m an idiot. For some reason I assumed that the yeast would have a viability of only 20-30% after being kept in the freezer for a year. I most likely massively overpitched. Lesson learned, always do more research than you think you need. Can anybody weigh in with their experiences storing dry yeast in the freezer for extended periods of time after opening? Thanks.

I wouldn't freeze yeast , fridge is good enough and will remain viable for 6+ months. . in 12 years have never froze yeast. Unless you do it right, cell damage can make it useless.

Overpitch is better than under pitch . I don't think the things you are seeing are from too much yeast

 

[Brew Cat]

that does seem a fast fermentation but it didn't finish
did you have a lot of simple sugars in your recipe?
those might finish faster than the rest of your wort
I never used that yeast so just throwing stuff at the wall

 

[Brewer #440722]

1) starters for dry yeast are unnecessary, they have all the nutrients they need in the pouch.

2). couldn't tell ya why bubbling wasn't what you expected, maybe you have leak and it only bubbled once pressure was high enough? 6 hours of fermentation seems unreasonable

3) bitter is usually from hops. What is your hop schedule?

4) what are measuring ph with? That just seems high. Most of my batches as in the low 5s

Thanks for the reply.

1. The reason I made a starter was to make sure I didn’t underpitch and since I stupidly assumed that cell viability would be very low, I made a three stage starter.

2. I’m pretty sure there was no leak since when I pressed the lid of the fermenting bucket, water in the airlock bubbled.

3. Admittedly, hops are the ingredient I know the least about, so I just followed a schedule I made on Brewfather to get the needed IBU. Should have ended up with 20 IBU. I added 5g Centennial at 40 mins and 15g of the same hops at 5 mins.

4. I bought a Milwaukee Instruments pH54 meter and calibrated right before measuring. I think I may have super alkaline water, which would explain why the acid addition didn’t lower the mash pH enough. Will get my water tested to confirm that.

 

[Brewer #440722]

I wouldn't freeze yeast , fridge is good enough and will remain viable for 6+ months. . in 12 years have never froze yeast. Unless you do it right, cell damage can make it useless.

Overpitch is better than under pitch . I don't think the things you are seeing are from too much yeast

Regarding freezing, I never once had issues with opened frozen yeast packs.

 

[Brewer #440722]

that does seem a fast fermentation but it didn't finish
did you have a lot of simple sugars in your recipe?
those might finish faster than the rest of your wort
I never used that yeast so just throwing stuff at the wall

I mashed at around 64C, so I guess it created a good amount of simple sugars.

I will leave the beer to mellow out over the next few weeks or more. I read that an overabundance of yeast in suspension can also cause bitterness. Is that true?

 

[Minbari]

64C will produce a very fermentable wort

Hop amounts seem low, so that is not it. Since it finished so fast, there is likely allot of yeast in suspension. Cold crash if you can, otherwise time will sort it.

I would consider using RO water and then adding brew salts to get the profile you want. Ph will be more predictable.

One other thing, if you are using tap water, are you sure there are no chlorimine in it?

 

[Brew Cat]

it does

 

[HighVoltageMan!]

I also tasted the brew and it had this strong bitter taste to it, something I’ve never tasted in my beer before. The only two things that I did differently this time were a small lactic acid addition (3.5ml) and using a starter. Even after adding the acid, mash pH after 20 mins was at 5.77.

(For context, once I got my pH meter, I made a test batch without adjusting water chemistry and using only Pilsen malt. The mash pH was 6.37 at 20 mins and 6.24 at 60 mins. I plan to get my water tested to see the Bicarbonate level. For now I’ll stick to distilled/spring water with clearly declared ion concentrations)

Two things can cause this. First yeast is very bitter and tart, yeast suspended in beer is not my favorite. Second, if it's not a typo, +6 pH is not good at all. Tannins get leached out of the grain in the mash and they are very bitter and harsh. This high pH in the mash effects finish pH, which is likely high, causing a harsh finish as well.

I freeze all my dry yeast. Freezing is not harmful, but not necessarily beneficial. Keeping it in the refrigerator works just as well, but I have a habit of keeping it in the freezer.

The other problem I see, is the starter could have been done with one step. When the yeast are stepped up, it's a general rule to increase volume by 10 for each step. I don't always increase by 10, sometimes I bump it up by a factor of 4. When I build a starter for my lagers, I use 1 pack (11 grams) of dry yeast in a 4 liter starter and keep it on there for @ 20 hours, it goes from 125 billion to 600 billion cells. By then it's near terminal gravity, but I never want a starter to hit terminal gravity so that the yeast are still metabolically active when pitched or crashed cooled. The yeast is in a healthier state and will start and finish faster when the starter isn't allowed to hit terminal gravity. You made a good point, when ever liquid yeast is used, even from a dry yeast starter, it's important to aerate the wort at pitch.

When you take a starter and keep it running through the same size starters you are beating up your yeast more then anything, they run out of food and they are stressed by it. You would have been fine with a single step 1.5-2.0 liter starter.

 

[HighVoltageMan!]

I would consider using RO water and then adding brew salts to get the profile you want. Ph will be more predictable.

This is good advice. Water can be as complicated or as simple as you want. My opinion is that the water is often over complicated by some brewers. Keep it simple, add a little water salts to RO for some calcium, that goes along way in improving beers.

 

[Donoroto]

strong bitter taste to it,

Possibly the beer just needs some time to mellow. A week’s time will show big improvement if this is the case.

Sometimes I get a harsh, almost acidic and grassy bitterness. It fades in a week or two. Almost always in hoppy beers.