Yeast Volume & Yeast Influence

[Beerlust]

Hi guys.

 

I admit my knowledge of yeast influence is at a relatively 'newby' level given the wide variety of yeasts available out there for brewing. I understand the literature I've already read & what is claimed, but from a practical brewing standpoint I've rarely tested it to any real degree.

 

To cut a long story short, I have recently been experimenting with a handful of different yeast strains with pretty much an identical recipe base.

 

As part of that experimentation, I re-brewed a recipe with the same malt bill, the same hop bill & the same yeast. The only difference was that I pitched a larger volume of yeast at the latest version by making a starter of this yeast that I did not do with the first brew.

 

The second brew is much more malty & yeast influenced to drink than was the first brew of this recipe.

 

My feeling is that this is possibly due to pitching a larger volume of yeast.

Is there any substance to that theory?

 

Can pitching a larger volume of yeast impact on the final flavours of a beer?

 

All thoughts welcomed.

 

Anthony.

[Hairy]

What do you mean by "yeast influenced to drink"?

 

Does it taste like yeast in suspension or do you mean estery like Belgians are sometimes referred to as yeasty?

[antiphile]

Gday Lustman

 

I have to admit I'm very surprised by your observations. I have to admit my working with yeasts and various experiments would suggest the reverse. But then again, there are so many variables that it's also nearly impossible to really reproduce exactly the same conditions: aeration levels, pitch temp, ferment temp etc etc. Even taking just the beer "balance" into account, the hop batch, storage, crop year, time since pelletising etc all change things.

 

I still get surprised often. For example I'm waiting for the fermeezer to become available to put down a marzen recipe I thought might be nice, so since the ambient weather here is perfect for ales, I did an all grain golden ale on Wednesday. It was ready for pitching about 6:30 pm. The Nottingham yeast was rehydrated and aerated in cooled second runnings (around SG 1.028) for 90 mins. I took a reading this morning, and the wort SG had dropped from 1.048 to 1.013 in 40 hours! I know Nottingham is a quick performer (and I used 2 X 11.5g sachets in 40 litres), but I was pretty stunned at the speed given this brew has never reached 19C since pitching, and has averaged 18C.

 

However, I still really like hearing about your (and others) results, Big Man, so I can keep learning.

[Scottie]

Gday Lustman

 

I have to admit I'm very surprised by your observations. I have to admit my working with yeasts and various experiments would suggest the reverse. But then again' date=' there are so many variables that it's also nearly impossible to really reproduce exactly the same conditions: aeration levels, pitch temp, ferment temp etc etc. Even taking just the beer "balance" into account, the hop batch, storage, crop year, time since pelletising etc all change things.

 

+1 you're a smart man Phil

You could experiment by splitting a batch but variables still exist.

 

Cheers

Scottie

[antiphile]

...you're a smart man Phil

 

Hi Scottie

I have the utmost respect for you, sir, but sometimes you really do force me to question your judgement!

Cheers, Philby

[PB2]

As an example, the Danstar Munich Wheat Beer spec sheet states, "When 100g active dried yeast is used to inoculate 100 litres of wort, a yeast density of 5-10 million cells per millilitre is achieved. The pitching rate may be adjusted to achieve a desired beer style or to suit processing conditions."

 

Usually pitching a smaller amount of viable cells and fermenting at more elevated temperatures will throw more yeast driven characteristics.

 

A good example of trying to get a cleaner brew with less yeast bi-products is the recent ROTM, using two sachets of W-34/70.

[Beerlust]

Hi Hairy, Phil, Scottie & Paul.

 

Thanks for your comments here. They are appreciated.

What do you mean by "yeast influenced to drink"?

 

Does it taste like yeast in suspension or do you mean estery like Belgians are sometimes referred to as yeasty?

I probably wasn't as clear as I should have been. The beer was noticeably maltier to the taste compared to the first brew using the same ingredients etc.

 

I just began to ask myself why?

 

Was it because I used older hops? I don't believe so.

Did I sparge a larger amount of liquid from the mash? I don't think so.

So I asked myself' date=' what else could it be?

 

Actually, I just went back through my brew day notes (again) & believe I may have found the answer. The second brew I upped the ferment volume to 23 litres (from 21 litres) & increased the chocolate malt addition by 25gms. Could this be the culprit? [img']unsure[/img]

 

Cheers,

 

Anthony.

[antiphile]

Hi again Lustman

 

I'll clarify my previous response to highlight the vagaries and a few different factors that affect the final balance (ie. malt forward or hop forward beers). It's great you keep good brew logs and they will also help to find the cause(s).

 

If you're doing a partial, then you also have to take into account

(a) the mash temp (a lower temp will create more simple sugars that will ferment out more fully and therefore give a higher attenuation and less "malty taste"); and

(b) the water/grain ratio (a higher ratio, i.e. a thinner mash, will also reduce the final sweetness and give a fuller attenuation resulting in a "drier final beer".

 

So, if a partial, I'm not sure if you changed the volume of mash water (in proportion to the chocolate malt PPG), or the sparge volume, or added more water for the boil, or the temp for any of the steps etc. I know I'm making this more and more complex, but "easy" isn't something I do well.

 

Cheers

[Beerlust]

Ahn nyeong my Korean immigrant brew buddy!

 

I like your take on this one Phil.

 

Given that I only do partials, I'll be honest & say I'm not overly fussy about maintaining a specific or exact temperature of the mash, as long as it is between 65-68°C, I'm happy. And perhaps as you suggest, there in lies the potential for fluctuations in my brews of the same recipe.

 

I rarely brew the same recipe twice, & the ones I have done are rarely that close together after one another, so that's probably why I haven't noticed this before.

 

There was nothing negative that came from this as the beer was still very enjoyable, but it did create a noticeable difference, albeit a small one.

 

I've certainly learned something here.

 

Thanks again,

 

Anthony.

 

[Canadian Eh!L]

I've found that if I overpitch the yeast and end up with having to use a blow-off tube it makes for a different tasting beer. I'm not sure if its because most of the yeast blows out of the FV by-way of the blow off or something else I'm not sure (this resulting in a possible underpitch). The different taste might be described as maltier. It's definitely not great. That's for sure.