Confused about lagering times and temperatures

[Mardoo]

Caution, anecdotal blather follows:

I've oxygenated starter wort and gone on to use a stirplate as normal. There is what appears to be an increase in yeast mass produced versus same yeast without O2, but I haven't measured it with precision as I lack the proper equipment. O2 - plate - drop yeast in fridge - pitch. It hits the ground running and ferments out amazingly quickly. 48 hours.

Too quickly for me. I decided to back off on O2 in starters and only oxygenate after pitching in the full brew. I get much closer to the performance I want. I was seeing very, very little ester development from yeasts like Wyeast 1469.

As I say, this is purely anecdotal as I lack proper means of measurement, nor have I run trials with the intention of working it out. It's entirely possible that the fast ferments were due to overpitching from more growth than I expected. Once I started measuring slurry from my starters with added O2 I was definitely ending up with more yeast than when I didn't add O2.

 

[Eagleburger]

That agrees with my anecdotal evidence. The only off flavour in my lagers has been diacetyl. I am a lacking ale in my keezer atm, bu5 my next lager will be fermented in two lots. One with no oxy an plenty of yeast, other with plenty of oxy but little yeast. I believe the oxy catalisid AAL-> diacetyl reaction or lack of is my problem.

 

[Mardoo]

Hey Manticle, should some portion of this be split off into a Yeast Starter - Theory and Practice thread?

 

[manticle]

Probably if people want to continue the conversation. Will re-examine tomorrow at the work pc.

 

[rude]

I did start a yeast topic on yeast starter step up as I was getting a bit off topic plus confused too
All good now though

 

[Trough Lolly]

Drifting slightly off topic, but yeast management is integral to making good lager, so perhaps not too far OT.
Ideally we need a lot of health yeast if we want to pitch cold, unfortunately a lot of the methods mentioned here may give you a lot of yeast but I would question its health. One of the vital ingredients in yeast propagation is Oxygen, without the right balance of O2 and other nutrients the yeast can be very stressed and can produce beer that is seriously flawed.

Make a special starter wort at about 1.040 (give or take), use the recommended amount of nutrient, and aerate to 10ppm with O2. Starters should be stepped up 10X in volume and you should see a 6-8 fold increase in the population at each step. Do the numbers, work out how many cells you need and what you think you are starting with that will tell you how many steps you need. I wouldn't assume the maximum population increase (I use 6X) as the danger of over-pitching is dwarfed by the problems caused by under-pitching .
Personally I like to run the yeast through its full life cycle, Pitch, allow to complete fermentation and settle out, remove the top layer and add more well aerated wort, as many times as necessary to get the population I want.

It might sound a bit tedious, but that is what it takes to make really top quality Lager. Some time ago there was an article by the head brewer at Budvar that said they pitched 5L of heavy yeast crem/Hl, works out to about 64 smack packs in 20L, I don't seriously expect any home brewer (myself included) to have those sort of pitches available, but more is better when it comes to pitching lager yeast.
Mark

I'm with Mark on this one...I find my best lagers result from healthy, not tired, yeast and remember, you can't assume that lager strains grow as vigorously as ale strains do. Fresh ingredients, temperature control and patience are the keys to a good lager.

Cheers,
TL

 

[galactaphonic]

Would either of these ideas work with the aim of getting bigger yeast populations?

1) Ferment half a batch size (e.g. 11.5 litres) and, when that has finished fermenting, add the second half of the batch in with the first half(making a final total of 23 litres).

2) Ferment one full batch, after fermentation is complete, leave it out of the fridge for a few weeks while you add another batch directly onto the yeast cake. After the second batch is finished, remove it from the fridge and then put the initial batch in for 4 weeks lagering, then when that's finished put the second batch in for lagering (this would mean they would be out of the fridge for several weeks in between the fermentation and lagering periods).

 

[manticle]

For 1, google drauflassen.

 

[manticle]

2 sounds weird.

 

[DJ_L3ThAL]

Would either of these ideas work with the aim of getting bigger yeast populations?

1) Ferment half a batch size (e.g. 11.5 litres) and, when that has finished fermenting, add the second half of the batch in with the first half(making a final total of 23 litres).

2) Ferment one full batch, after fermentation is complete, leave it out of the fridge for a few weeks while you add another batch directly onto the yeast cake. After the second batch is finished, remove it from the fridge and then put the initial batch in for 4 weeks lagering, then when that's finished put the second batch in for lagering (this would mean they would be out of the fridge for several weeks in between the fermentation and lagering periods).

You need the bigger yeast population BEFORE you brew, so your point 2) suggests you already have enough yeast for the first batch and whether you do another batch after it or not is not within context?

 

[Eagleburger]

For 1, google drauflassen.

Cool, it has a name.

 

[balconybrewer]

Quick question. How can you calculate ppm of dissolved O2 when the volume varies.

All of the above talks about 1-2l/m for a 23l batch, but obviously this changes if you were trying to oxygenate a small
Starter of double batch.

Cheers

 

[Black n Tan]

Quick question. How can you calculate ppm of dissolved O2 when the volume varies.

All of the above talks about 1-2l/m for a 23l batch, but obviously this changes if you were trying to oxygenate a small
Starter of double batch.

Cheers

Double the batch, double the time. So for a 23L batch use 1 minute at 1l/min and for 46L batch use 2 minutes at 1L/min. I don't use oxygen for starter as a stir plate provides better results than just oxygenating at the start.

 

[balconybrewer]

Anyone else got a calculator, chart or other method of calculating O2 ppm based on flow rate / time and volume?

 

[MastersBrewery]

I think the above is the accepted pratice and I haven't seen any other methods widely used.

 

[wobbly]

Interesting post by Rude.

Funny you should say that Galactaphonic because the other day I had a munich dunkel brewed with a wyeast lager yeast
It was brewed with a williamswarner unit at my local LHBS it was very nice
The bloke told me that it was drinking at 13 days ofter fermentation due to it being under pressure clear as a bell
Ales only 7 days problem was the price of the unit
This got me thinking along youre lines above as well
Just thought I'de share but no idea on lagers really never brewed one but it is on the cards good thread for me cheers

Fermenting under pressure and the processes recommended when brewing with a WilliamsWarn is/maybe a "Paradigm Shift" in conventional thinking about brewing and lagers.

In post #2 MHB talks about why you need large starters and time (primarily because you are fermenting colder to prevent unwanted esters etc) also that you need time (many weeks) to get the yeast and cold break to settle out
Fermenting under pressure limits (even prevents) the formation of esters and other off flavours when fermented at higher temperatures (15/18C for lagers and 23C for Ales) and the higher temperature means fermentation is over and done with in about 4 to 6 days

In the WilliamsWarn yeast and cold break still in suspension after only 12 hours cold crash are removed by the use of two doses (1st 30mls and 2nd 20mls) over 48 hours of Colloidal Silica Oxide. I accept that this doesn't meet the German purity laws.

A WilliamsWarn isn't/doesn't tick most/any boxes for most on this site but as stated by "Rude" above it can and does result in a very nice beer

Cheers

Wobbly

 

[MastersBrewery]

Wobbly,
I have to disagree, the WW ticks alot of boxes.
The price box is the biggest of all, this is the box it missed.

MB

 

[MHB]

Pressure fermentation has been getting quite a few mentions of late - enough to make me go and read up on it - not enough there to interest me in doing it.
It isn't a magic bullet, it can have some advantages but there are potential drawbacks to. The idea was developed to reduce Diacetyl in lager brewing and get faster maturation. The pressure isn't applied until 50% of the fermentation is complete, the temperature is allowed to rise to around 20C and the applied pressure is much less than some home brewers talk about using, very large (commercial) yeast pitches are required - if you get it wrong there is a big chance if dramatically increasing the amount of Acetaldehyde, getting incomplete attenuation and other metabolic side issues all of which you don't want. The target pressure is enough to give 5.5g/L of dissolved CO2 at lagering temperature (~1oC) so we are talking roughly 80kPa.

I think pressure fermentation would be best left to the big brewers with high-end temperature, pressure, rate of rise monitoring and a burning desire to knock 7 day out of a 28 day brewing cycle, me I would rather be patient.
Mark

 

[wobbly]

The comment that pressure isn't applied until 50% of fermentation is completed isn't consistent with the WilliamsWarn process.

When fermenting a Lager (or Ale) the pressure is allowed to progressively increase from the very start of the ferment up to what ever pressure setting is set on the Variable Pressure Relief Valve.

Using one packet of W34/70 in 25lt of 1.055 wort at an initial temperature of 15C (for the first 3 days followed by a further 3 days at 18C) the pressure will build to the VPRV setting which in my case is generally around 1.5bar (21psi) in about 36 hours which is only about 25% of the total ferment time of 6 days

Also MHB infers that around 80kPa (11psi) is the norm for lagering conditions where as the WW process towards the end of the ferment is about twice this value at around 1.5bar (22psi/160kPa)

As far as the need to use "very large (commercial) yeast pitches" this is not the requirement in the WW with wort below 1.060 where I X 11.5g packet is all that is required. For worts above 1.060 then 2 X 11.5g packets is recommended

This post isn't about challenging what MHB has posted, rather highlighting that pressure fermenting in a WW is a "Paradigm Shift" in traditional Home Brewing - albeit at quite a significant $ investment

Cheers

Wobbly

 

[MHB]

I could easily think you were challenging what I posted, except that in a couple of respects we are talking at cross purposes.
I am sighting the research that has been done on pressure fermentation to reduce Diacetyl and accelerate maturation (read Kunze and a couple of other references) whether or not a manufacture of a piece of brewing equipment has applied that research to best effect is another question entirely, it does not however negate what the research indicates is best practice.

The 80kPa referred to is as part of the maturation process, it is obviously too low to be the carbonation pressure for a Lager, which would be the endpoint pressure in the WW.
The WW is an novel piece of kit with many interesting applications of what is quite old/common commercial brewing process to home brewing, If I had the spare $'s I would be happy to own one, but be aware that it is far from being a Paradigm Shift (nice marketing but not really true) and that the designer has (for economic reasons I suspect) made some compromises and that there may be a better ways to apply the knowledge we have.

Just remember that a good blurb isn't research
Mark