Seeking higher attenuation

[curnes]

I brew high gravity ales-IPA mostly (I am a North westerner after all). Starting gravity is about 1.060-1.070 and I brew 15 gallons at a time with a couple of friends. Our fermentation always stops at about 1.020 and our beer is pretty good. We would like to ferment down a little lower, to about 1.015 but do not seem to be able to get past our current numbers. Here is what we have been trying:
1. Yeast starter. Starting with one batch of Yeast and making a starter a couple of days before brewing. We usually start with about a quart or so of starter. Don't know how many yeast cells we've been pitching, I keep trying to get my buddies to count them but they refuse.
2. We recently got an oxygen tank and stone. We put the O2 in the fermenter (a 15.5 gallon keg) when we are filling from the wart chiller. We are always at about 70-75 degrees when we fill the fermenter. We also always have vigorous fermentation within 24 hours. This seems to be a pretty messy process. Foam everywhere!
3. We recently went to WP007 yeast because I read that it had a high attenuation rate.
Any other ideas of ways to bring our final gravity down?
Thanks
Cameron

 

[Tinga]

your starters could be quite a bit bigger 2-3 times that size

also you can try using amylase. this enzyme breaks down the complex sugars that are giving you a higher gravity and the yeast can eat those guys up. here is a thread about it.
https://www.homebrewtalk.com/f39/using-amylase-enzyme-beano-restart-stuck-fermentation-111576/

 

[COLObrewer]

A quick calc with mrmalty says you need 6.51 liters of starter for 15 gallons at 1.060 or are you using 1 quart per 5 gallons? You can go to www.mrmalty.com and enter your specific parameters to get closer to what you need. I believe your yeasts are being stressed.

 

[kanzimonson]

Good lord, I can't believe someone is already jumping in with the amylase comment - there are so many other solutions before trying amylase.

First, we need to clarify about your pitch rate. As COLObrewer said, 1qt is not even close to enough yeast in 15gal. Use Mr Malty to figure out how much to pitch.

Also, are these all grain or extract batches? If extract, some extracts are less fermentable than others. You could try switching brands.

Whether it's all grain or not, you could sub out somewhere between 5-10% of your extract with granulated sugar with practically no effect on flavor. We're talking somewhere between .75-1.5# substitution for the same amount of extract, or about 1.5-3# of base malt if you're doing all grain.

 

[Tinga]

oh if its all grain i suppose you could mash lower.... should have thought of that before.

 

[o4_srt]

If all grain, mash at a lower temperature. I just brewed a cream ale containing 1 lb of flakes rice and .5 lb of corn sugar. Mashed at 149 for 90 minutes per "brewing classic styles" to increase fermentability.

It has been fermenting strongly now for 4 days with no end in sight. Hasn't even slowed.

 

[ArtVandelay]

edit: just saw that my suggestion was already mentioned.

 

[erikpete18]

If you're all-grain, I'd definitely go with the previous response and mash lower. If you're extract, then you don't really get to control mash temps. It won't help if you're trying to fix a current batch, but if you're brewing higher gravity extract beers, its perfectly fine to replace some of the malt extract with sugar. Don't go overboard, but any where from 10-20% of the fermentables could come from sugar, depending on the OG (1.070 try to stick to around 10%, >1.100 20% wouldn't be out of the ball park).

You'll want to make sure you can keep your temps low to avoid cidery flavors, and might consider adding the sugar a day or two after primary fermentation starts so that you don't get any stuck fermentations, which was exactly what you were trying to avoid!

 

[permo]

15 gallons of 1.070 wort with a 1 quart starter? That is severe under pitching. WLP007 if a huge attenuator, but for 15 gallons of beer that big, I would make a very, very large starter, I make a lot of 6 gallon batches of IPA with WLP007, WLP001, Pacman, etc..etc.... and I try to make a 1 gallon starter and I finish nice and dry. So according to my experience, I would recomend a 3 gallon starter.....some would say that is overpitching, personally it works great on my brews.

 

[curnes]

Hi Guys,
Thanks for all your great responses. I have been on vacation in New Mexico for the past week so ignoring the forum. We are all grain brewers and I have really been trying to convince my partners to lower our mash temps, with some success as of late. It looks like what we need to do next is be sure we pitch a lot more yeast, perhaps a few gallons of starter. We have been somewhat limited with space in our fementer, but I think that can be easily remedied by splitting the batch into two fermenters. We often rack our brew into the existing yeast from the last batch so it is difficult to know exactly how much yest we are starting with.
Thanks again for the suggestions.
Cameron

 

[Calder]

Racking onto a previous cake, is over-pitching, so amount of yeast is probably not the problem. I would recommend using a quarter to a third of a cake of a same size batch.

Mash lower around 150 F. Get extra thermometers to ensure they are correct and check for temperature differences within the mash.

Sub in 5 to 10% cane sugar.

Use PacMan.

 

[Yooper]

Racking onto a previous cake, is over-pitching, so amount of yeast is probably not the problem. I would recommend using a quarter to a third of a cake of a same size batch.

Mash lower around 150 F. Get extra thermometers to ensure they are correct and check for temperature differences within the mash.

Sub in 5 to 10% cane sugar.

Use PacMan.

NOT for 15 gallons, it's not!

I'd still suggest mashing at a lower temperature, and double checking the thermometer, but definitely consult mrmalty.com 's pitching calculator and pitch enough yeast!

 

[Calder]

NOT for 15 gallons, it's not!

Sure it is. If you are pitching 15 gallons on the cake from a 15 gallon batch. The yeast will not reproduce as much as would be ideal, so you will be dealing with stressed yeast, reduced yeast flavor contribution, and I believe increased fusels as a result.

 

[curnes]

We pitched about 3 gallons of yeast starter into 16 gallons of IPA with a starting gravity of 1.070 today. Looking forward to a lower finishing, maybe 1.012(?) We used WPL007 yeast and I am concerned that it will cake up and we won't be able to use the yeast again. Any experience with this?

 

[johnnyboy1965]

I suggest you try dried Nottingham yeast. It will get down to 1.010 with no problems at all, even with your high SG

 

[kanzimonson]

That's a pretty big beer to be reusing yeast. The common wisdom is don't reuse yeast from a beer that has more than 5-6% alcohol.

But to answer your question, I use 1968 in most of my ales which is probably the most notorious flocculator. Basically, I still attempt to rinse the yeast, but when it's all done I end up with about 25-50% trub in my collected slurry. I can either worry about it, or not, so I don't.

 

[jar1087]

I recently brewed two DIPA's with OGs of 1.071 and 1.072 respectively and reused WLP007 yeast from previous batches. The first finished at 1.008 and the second should be there soon. I actually do a two rest mash, first at 145F for about 30 mins and then 155F until conversion is complete, before mashing out around 170F. I would definitely recommend mashing at a lower temperature, maybe 149F for a single rest mash, or try the two rest mash if that doesn't do it. Also, I would actually reduced the amount of yeast that you are pitching, as recommended above; definitely not more than half of the previous yeast cake, assuming that you are brewing the second batch within a month or so. I also second checking out mrmalty.com for more precise pitching rates.

 

[jar1087]

I should also mention that I used ~5% sugar in both batches.

Could you post your grain bill as well? A lot of crystal malt could also adversely affect your FG.

 

[curnes]

Hi Guys,

I appreciate all your thoughtful comments. Our grain 45 LB two-row and 3 LB crystal 40. We are fermenting in 15 gallon stainless kegs. These are the small barrels that sit on their sides with the bung in the middle of the keg. It is pretty much impossible to get the caked yeast out without a lot of contamination, due to the small bung hole. So, whenever possible, we pitch on top of the old yeast. When we used other yeast that stayed pretty fluid, we could just pour it out into a couple of sterile containers and reuse it immediately or refridg. for a week or two. We use these to ferment in in the cool weather (way too long in the northwest) because we build an insulated box around them.

Now that it is warming up, we have a couple of conical fermenters that we can use and we won't have issues of getting the beer or yeast out of the kegs.

I'm anxious to see if we got this batch to ferment to 1.015 or below.
Cameron

 

[weirdboy]

I recently made a batch of >DIPA that had an OG of 1.101 and finished up at 1.010.

I mashed at 150F and pitched 4 (old) packets of US-05 on it. Also I added 2 lbs of sugar in a simple syrup after the first week of fermentation. So I guess without the sugar the OG was more like 1.086.

Granted, not a 15 gallon batch but I know for a fact it can be done.