Farming and Washing Yeast

[Bachy__]

Hello, Im back. I lost this website for a month and only found my way back tonight So far I have had four successful batches since my opening thread and am really getting into brewing. Anyway, I want some thoughts on yeast farming and yeast washing. So far in my personal experiment I have done the following although next time I will try the info in the locked thread (now that I'm back).

I pitched wyeast 3068 (liquid yeast) into a starter made of wheat malt in a 2 litre coke bottle (with airlock). After 2 days fermenting I poured off half of the 'beer' and topped up my wheat malt mixture. After about 5 days total I chilled it - poured off the beer, poured in boiled (cooled) water and rechilled. I replaced the water a second time and split the mixture into 6 beer bottles.

Now as an experiment (and a batch of beer hopefully) I pulled out 2 of my bottles and made two starters. One with raw sugar and one with malt enhanced brewing sugar (each in a coke bottle with airlock & both boiled and cooled). When I make the beer should I rewash the yeast; should I chill and pour off the beer with the yeast going into my fermenter; or should I pour the whole starter straight into the fermenter without chilling? If I was to continue my coke bottle method is 1.5L starter (roughly) enough for one batch or should I make up a larger starter?

Another thing I have heard is that washing the yeast with an 'acid wash' as opposed to a water wash I have done already will reduce the chance of infection. Does anyone have experience with acid washing (I gather from other websites that phosphoric acid or Chlorine dioxide are the most popular). Do you have a preference of either? Where would I buy either of these (I'm assuming star san is not a good substitute)? When washing I assume you check the ph to ensure a ph of 2 - 2.5 for the wash?

[drsmurto]

Raw sugar for a starter is a big no no.

There are 0 nutrients in sugar vs malt extract which is why it says on the back of the liquid yeasts (and in my locked thread about yeast) to only use malt extract in the ratio of 1g/10mL of water.

Not wanting to sound too arrogant, can you read the locked thread on 'Making and storing liquid yeast starters'.

This will answer all your questions.

It may be ok but i have never used sugar in a starter so i dont know how bad a shape the yeast are now in.

IN the future, use only malt extract.

As for pitching the entire yeast starter vs chilling, pouring off the 'beer' and only pitching the yeast slurry that depends.

Are you happy adding extract to your beer? If you arent making an all grain beer this is the simplest option.

[Bachy__]

'Not wanting to sound too arrogant, can you read the locked thread on 'Making and storing liquid yeast starters'.

This will answer all your questions.'

Like for example my question regarding acid washing. If that thread had the answers I wouldn't have asked.

Care to explain nutrients? To my knowledge yeast only requires various sugars for energy it is not interested in anything else except a moist enough environment that provides enough oxygen and warmth. The only issue that can arise (to my knowledge) is that a yeast raised on one sugar will have lag time due to digestion difficulty of the new sugar. Strains of yeast also prefer certain sugars over others. The second sugar I used contains several important yeast foods and included maltose which should prevent lag time as the yeast will mainly be fermenting maltose in my particular beer. For the present batch I am using a liquid wort and didnt want to open it 1 week prior to brewing (for obvious reasons) and was stuck looking for alternatives that would be the most similar to the wort.

Re Your other post -- I have no idea what LDME is.

[Trough Lolly]

Apologies for crashing in on the conversation, but Doc is spot on - simple short chain sugars such as cane sugar or dextrose will provide carbs but absolutely none of the other vital yeast nutrients that are present in barley extracts.

To quote a post I made back in 2006 on another forum:

Yeast require a number of nutrients for growth, including vitamins, minerals, carbs, nitrogen and trace elements (including copper and zinc). A good source of nitrogen comes from the amino acids found in the wort ((or malt extract for that matter)). Yeast cells use the nitrogen to develop cell proteins and other compounds. There are roughly 20 amino acids and they are commonly found in the malt extract / wort that we use in beer brewing. All of the wort amino acids and the small peptides are referred to as Free Amino Nitrogen or FAN. The FAN level in your wort is a good indicator of potential yeast growth and therefore fermentation performance. Cheap malt extracts are often low in FAN. A typical all malt freshly mashed wort has around 150 to 220 mg of FAN per litre. So any decent yeast nutrient should contain FAN...
Now, yeast has FAN levels of around 2% by weight, so, if you want to increase the FAN levels in your wort, you could toss in some yeast in the boil (I normally add it with about 10 mins to go). Ok so it doesn't add all that much FAN but it does also add some zinc to the brew - which is an important yeast growth contributor - and whilst it's not a lot, it's better than tossing the sachet into the bin...There are other contributors that the yeast cells surrender, such as Vitamin B, but I think you get the point without boring you with too much more detail!
The boil does kill the yeast and it violently erupts the cells - as opposed to the cell breakdown via autolysis - so the boil assists by releasing nutrients into the wort from within the cells and even the cell walls themselves, which will help the fermentation yeast that's eventually pitched after the wort is chilled. Some brewers add modest quantities of bakers yeast to their boil to provide a relatively cheaper nutrient to brewing yeast...
An alternative to this rather murderous endeavour is to purchase some true yeast nutrient, typically food grade mono or di-ammonium phosphate which is a good nitrogen source.
A note of caution - don't just buy kilos of bakers yeast or yeast nutrient and upend it into the kettle - too much of this stuff will result in a horrid undrinkable and potentially dangerous beer.

The original post is - here...

Oh, and LDME = Light Dry Malt Extract - a key ingredient for effective yeast management.

Cheers,
TL

[Bachy__]

Thanks.

That was a very useful answer and what I was hoping for.

How about with regards to acid washing of yeast -- Is there someone with experience with that and is it useful? Do homebrew shops supply the chemicals (Phosphoric acid or Chlorine dioxide) and has there been an improvement on taste by controlling contaminants using this process? I'm guessing its a bit of a controversial topic but I'd like to hear from someone who does do it or has done it and the results.

As you would expect from the information in your above post my plain sugar yeast is looking a bit sad although it has grown a bit. The malt enhanced sugar yeast has significantly outgrown the plain sugar and looks much healthier.

[Trough Lolly]

Ant Hayes wrote an interesting primer on acid washing:
http://oz.craftbrewer.org/Library/Metho ... Wash.shtml

I harvest slurry, give it a wash without acid and use that instead:
http://www.schwedhelm.net/brew/yeast_harv_freeze.html

Chillers article on yeast farming on aussiehomebrewer is also useful - but essentially, Doc's excellent article covers the same info:
http://www.aussiehomebrewer.com/forum/i ... topic=3697

To be honest, acid washing is pretty hard core and if you regularly brew and like to use the same yeast strains, not all that necessary. A well managed collection of yeast that's regularly refreshed and re-used doesn't really need full on washing - but by all means go for it if you want to. I would be spending my time focussing on storing samples via slants or plating out your yeast library if you wanted a real challenge...

Cheers,
TL

[Bachy__]

Thanks, I'll read those links over the weekend.

I'm hoping to get into grain brewing eventually but at the moment I use liquid worts. With the ingredients constant I have been experimenting with yeasts and temperatures as I'm seeking to make a very specific beer that I can often brew with a similar high quality. I used to be a baker/pastrychef (different sort of yeast work) but I guess that has left its mark on me. If I made different quality products I got my ass kicked! I'm just trying to eliminate all variables here as I'm not the kind of person who 'chucks some yeast and sugar into a tub'. Its all gotta be calculated with all variables removed... One day I will make the perfect beer!


Edit: Yeah I'd already read that first link and its one of the links that got me interested in acid washes initially.

[drsmurto]

'Not wanting to sound too arrogant, can you read the locked thread on 'Making and storing liquid yeast starters'.

This will answer all your questions.'

Like for example my question regarding acid washing. If that thread had the answers I wouldn't have asked.

Care to explain nutrients? To my knowledge yeast only requires various sugars for energy it is not interested in anything else except a moist enough environment that provides enough oxygen and warmth. The only issue that can arise (to my knowledge) is that a yeast raised on one sugar will have lag time due to digestion difficulty of the new sugar. Strains of yeast also prefer certain sugars over others. The second sugar I used contains several important yeast foods and included maltose which should prevent lag time as the yeast will mainly be fermenting maltose in my particular beer. For the present batch I am using a liquid wort and didnt want to open it 1 week prior to brewing (for obvious reasons) and was stuck looking for alternatives that would be the most similar to the wort.

Re Your other post -- I have no idea what LDME is.

The comment to read the other thread was neither meant to be arrogant, nor meant to answer all your questions.

It did however give you a good start - which is why it is a locked thread. Nothing but gospel in that baby!

Acid washing and nutrients in extract and why they are needed have now been covered by TL, something i have neither read about nor done.

Sorry by answer was so short, i ducked on and saw your post and gave it a quick answer.