WLP005 finished below target gravity

[ChrisMoss]

Hey guys,

Still new here and new to brewing. Made a porter recently which had a target ABV of 4.8% - decided to add another 1.4kg of Maris otter to bump the ABV up (also because my previous mash/sparges haven't been all that efficient).

So, original gravity hit 1.072, target gravity is 1.017, but measured today (after 7 days at 21c, it's at 1.027. So 6%ABV, but still way under what it should be.

It was a 5gal (UK) batch and I used a single vial of wyeast WLP005 British ale yeast, well aerated wort I think but found after pitching that a little was still left in the vial.

So I have two questions - one - do you guys think this will continue to ferment? It's pretty quiet right now.

Two (more importantly I think) - when I bottle this - if I was going to bottle to 2.2vols co2, should I adjust this to take into account stuck fermentation so they don't over carb and produce off flavours in the bottle?

Thanks guys your advice is always invaluable!

Cheers

Chris

 

[jdauria]

As to it not finishing, one vial of yeast is not normally enough for a beer with a gravity over 1.050. A 5 gallon (US) 1.072 beer needs 249 billion yeast cells. A vial only has 100 billion at 100% viability. The older the vial, the less yeast you had to start with. Even two vials would be short, but would work twice as hard. Usually over 1.050 I would recommend a starter.

You can try rousting the yeast and just let it ferment for a few more weeks, maybe warm the beer up more too, or pitch some dry yeast (half a pack) to try to get it to finish. Did you taste a sample...at 1.021 it could still be a little sweet.

I don't bottle, so will leave that for someone else.

 

[RmikeVT]

Agreed with the above post. Another set of questions:

1) Did you take any measure to aerate such as pure o2 through diffusion stone, slosh around the wort for a while, or some other type of apparatus to to diffuse o2 into wort?

If you only used 1 vile and didn't aerate then you're probably not going to get the result you want on a 1.072 beer.

2) What was your mash temp? Recipes always list a mashtemp that is a bit high for my system for porter recipes. I always shoot 2 or 3 degrees below and usually hit the desired FG

Also, if you don't have the ability to make a starter or aerate your wort you should consider using dry yeast on your bigger beers. I find that s-04 and us-05 make fantastic porters. And you don't have to worry about pitch count, aeration, etc. I would, on a 1.072 beer HIGHLY recommend hydrating your yeast though.

That being said, you could probably pitch a pack of US-05 and get some added attenuation if there are still fermentables left in the wort.

Another thought: You especially want to be careful if you are botteling because if there is fermentables left over you could create bottle bombs.

 

[TheBigLebrewsk1]

As to it not finishing, one vial of yeast is not normally enough for a beer with a gravity over 1.050. A 5 gallon (US) 1.072 beer needs 249 billion yeast cells. A vial only has 100 billion at 100% viability. The older the vial, the less yeast you had to start with. Even two vials would be short, but would work twice as hard.

According to wyeast 1 package is enough for up to 1.060. So even at less than 100% availability it is sufficient for an ale wort of 1.050

 

[TheBigLebrewsk1]

Agreed with the above post. Another set of questions:

1) Did you take any measure to aerate such as pure o2 through diffusion stone, slosh around the wort for a while, or some other type of apparatus to to diffuse o2 into wort?

If you only used 1 vile and didn't aerate then you're probably not going to get the result you want on a 1.072 beer.

2) What was your mash temp? Recipes always list a mashtemp that is a bit high for my system for porter recipes. I always shoot 2 or 3 degrees below and usually hit the desired FG

Also, if you don't have the ability to make a starter or aerate your wort you should consider using dry yeast on your bigger beers. I find that s-04 and us-05 make fantastic porters. And you don't have to worry about pitch count, aeration, etc. I would, on a 1.072 beer HIGHLY recommend hydrating your yeast though.

That being said, you could probably pitch a pack of US-05 and get some added attenuation if there are still fermentables left in the wort.

Another thought: You especially want to be careful if you are botteling because if there is fermentables left over you could create bottle bombs.

I ran my numbers again and derived 227 billion, using 12 million per mL of wort over 1.060, per wyeast. So you are right.

I've been reading in depth about yeast and it's complex but not complicated.

 

[RmikeVT]

I ran my numbers again and derived 227 billion, using 12 million per mL of wort over 1.060, per wyeast. So you are right.

I've been reading in depth about yeast and it's complex but not complicated.

You can never go wrong making a starter and aerating.

When it comes to making an ale that isn't a hefe, belgian, saison or some yeast specific style you can't really go wrong with US-05 or S-04 and even Nottingham for that matter.

 

[TheBigLebrewsk1]

You can never go wrong making a starter and aerating.

When it comes to making an ale that isn't a hefe, belgian, saison or some yeast specific style you can't really go wrong with US-05 or S-04 and even Nottingham for that matter.

I think it more if a question of requirements to achieve the desired output. I personally stopped making starters when unnecessary. Over pitching isn't the best approach, it's pitching the right amount that yields the best beer with the right ester profile.

I started using S-04, it's easy to manage.

 

[RmikeVT]

I think it more if a question of requirements to achieve the desired output. I personally stopped making starters when unnecessary. Over pitching isn't the best approach, it's pitching the right amount that yields the best beer with the right ester profile.

I started using S-04, it's easy to manage.

The only problem I have managing s-04 is how quickly it ferments. I have use a cooler as a water bath to keep my fermentation temps in check, and s-04 due to its quick nature can really crank out some heat. Which, when s-04 gets on the warmer side can create some fruity esters that might be off putting to some. But if I am diligent and keep it under control I am typically pleased with the results. Especially, in my lower gravity beers, it adds a malty depth and leaves a little residual sugar behind to make a smaller beer seem a little fuller and have a bit more depth, where I've noticed US-05 is almost too clean.

 

[TheBigLebrewsk1]

The only problem I have managing s-04 is how quickly it ferments. I have use a cooler as a water bath to keep my fermentation temps in check, and s-04 due to its quick nature can really crank out some heat. Which, when s-04 gets on the warmer side can create some fruity esters that might be off putting to some. But if I am diligent and keep it under control I am typically pleased with the results. Especially, in my lower gravity beers, it adds a malty depth and leaves a little residual sugar behind to make a smaller beer seem a little fuller and have a bit more depth, where I've noticed US-05 is almost too clean.

I totally agree 100%. S05 WY1056 are just too clean for my palate. I love a hint of malt sweetness in my pale ales and IPAs that an English yeast provides. I think it adds a sense of depth to the palate and is just a better beer. In Texas a fermentation fridge is a must, I set my ambient temp to 59 degrees with S04, the heat production is significant for those first 3 days. Try WLP007 some time I think it's perfect for IPAs