BIAB Yeast Pitching

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Joeymacca

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Hi all!

I use the BIAB method to brew 3 gallon batches (so not full 5/6 gallon batches. My setup isn’t scaled up to that yet). I typically use liquid yeast. I’ve heard a couple opinions on how much of the liquid yeast pack to use:
1. Use the whole pack. It’s pretty much impossible to over-pitch yeast.
2. Use about half to two-thirds of the pack.

Just curious what other 3 gallon BIAB brewers do. I typically pitch the whole pack but my most recent brew finished at 1.015 when it was supposed to have an FG of 1.021 (my OG was 1.066). My last few batches have had similar results with the FG. So I’m wondering if I need to pitch less yeast.

Cheers
Joey
 

DBhomebrew

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I brew ~3.5gal batches, pitch the whole pack, and generally hit FG within a point or two.

Where are you getting your FG prediction?

Recipe as published? Take that as a very rough guideline.

Brewing software? Most do not figure grist into their FG prediction. All else being equal, a wort with lots of crystal will finish higher than one with 100% base malt.

More information about your recipes and process will get better responses as to why your FG prediction may be off.

Also, a whole pack or a half pack isn't really a good measurement of how many viable yeast cells are pitched. Is that pack 2, 3, or more months old? Was it kept at optimal temperature at all moments since leaving the factory? In other words, you're probably not over-pitching.
 

doug293cz

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It's more likely that your FGs are low because your wort had higher fermentability than expected. One thing to try is mashing 4°F - 6°F hotter than you have been. Another possibility, if you crush very fine, is that your gelatinization finished early during the mash, giving the enzymes more time to create fermentable sugar from the longer chain unfermentable carbohydrates. If you have a refractometer, you can monitor your SG in the mash, and terminate the mash when the SG stops increasing.

On the other hand, it may not even be a real problem. Do you notice any detrimental effects on the taste or mouthfeel? If not, then there's no reason to try to fix things that aren't really broken.

Brew on :mug:
 

palmtrees

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I brew 2.5 gallon biab batches. I now do a yeast starter for each batch, targeting enough cells for a 5 gallon batch so I can save half for the starter for my next brew. But before I did starters, I always pitched the full packet of liquid yeast. I found it too tough to measure the slurry in those packs or to store it for next time. And you aren't going to overpitch by much, if at all. Certainly not enough to bother with saving some of the packet. My fermentation has been much faster and healthier since doing starters, so I recommend doing it, if you can.

I wouldn't expect your pitch rate to effect FG at all. It will impact how quickly fermentation starts (ie, how long is the lag phase) and how quickly it finishes. An underpitch could impact the flavors imparted by the yeast. But as long as you have some healthy yeast and give it enough time, it will eat the fermentable sugars in your wort. If your FG is lower than expected, it's a problem with the software assumptions about your recipe or its because of your mash temp.
 

CascadesBrewer

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I brew a number of 2.5 gallon batches. The general thought is that 200B cells of yeast is the recommended pitch rate for a 5 gal batch of low-mid gravity ale. So I figure that one pack of White Labs or Wyeast (which have around 100B cells) is just about the perfect pitch rate for a typical 2.5 gal batch. I will typically direct pitch a pack. I often harvest and reuse yeast, so often I am direct pitching a pack of yeast into a 2.5 gal batch, and might pitch the harvested yeast into a 5 gal batch.

I agree with the others. Overpitching will not result in a lower gravity...other than underpitching can result in unhealthy yeast that are not able to finish fermentation.
 

RufusBrewer

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Personally I would not be afraid to pitch a White Labs, Wyeast, or any of the other liquid yeast brands directly into a 3 gallon batch.

Some homebrewers tend to go over the top on some top. In my mind, yeast starters and cell count is one one those topics.

Do some research on Shaken, Not Stirred (AKA Vitality) starters. If you want to feel like you are doing something more and really taking care of your yeast, this could be a perfect solution for you.
 

AlexKay

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2.5 gallons here, and a full packet. In fact, I use a full packet when I’m using dry, as well. I confess I’m not even entirely clear what the theoretical bad effect of an overpitch in home brewing might be.
 

madscientist451

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I chuck a whole pack in. When I'm re-using yeast I usually pitch about 1/2 what was saved, but if its been in the fridge for a while, I toss it all in. IMO over pitching is over-rated, (over worried about) however, under pitching can cause some problems in certain situations.
I don't have a clue how many billions of cells of yeast I end up using, but I usually use more than I should and the beer is fine.
Your recipe and mash temp will have the greatest impact on where your FG ends up if you pitch a heathy amount of yeast.
 

dmtaylor

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Use a whole pack for 3 gallons. Myself, I often brew just 1-2 gallons. For that I only use 1/2 pack. But in 3 gallons I would just use the whole thing.
 
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Joeymacca

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Just had a chance to look over all of the replies to my original post. Thanks so much to everyone who took the time to give their 2 cents. Sounds like my yeast isn’t the reason I’ve been having beer finish at a lower gravity than the recipe states they should. I’ll pay closer attention to my mash temp moving forward. I’m also thinking that fermentation temperature might be a bit too highI wish I had a fridge to put the bucket in, or some way of keeping the beer cooler while fermenting. The temperature in the room usually isn’t more than 65-70 degrees but I know once the beer starts bubbling away that raises the temperature of it.

Here’s the most recent recipe I brewed. A red ale.

Maris Otter - 5lbs 10.7oz
Munich - 1lb 5.2oz
Flaked oats - 6.4oz
Crystal 120L - 3.9oz
Crystal 30L - 1.9oz
Chocolate malt - 1.0oz

Chinook - 0.50oz (first wort 60mins)
Cascade - 0.50oz (20mins)
Cascade - 0.50oz (5mins)
Cascade - 0.25oz (1min)
Cascade - 0.50oz (dry hop)
Chinook - 0.50oz (dry hop)

Pacific Ale (white labs WLP041)

BeerSmith showed an OG: 1.070 FG: 1.021

I ended up with an OG: 1.066 FG: 1.012

The beer was tasty going in to bottles but definitely had a strong alcohol taste. Hopefully that mellows out in a few weeks.
 

palmtrees

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If you're getting a strong alcohol taste, that probably isn't due to the final gravity but rather fermentation temp. Sounds like you already know the issue, but you will get some fusel alcohols when fermenting in the mid 70s with a lot of yeasts. That gives you an alcohol burn. Is there any way you could do a water bath with ice chunks for your bucket in the first few days of fermentation? Frozen water jugs in a bathtub can work. Anything you can do to keep the temp in the 60s the first three or four days could give you some huge flavor improvements.
 
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Joeymacca

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Awesome tip, palmtrees. Years ago I bought a big soft cooler that the bucket can fit in. I used to use it during the hotter months but it was tough to keep it at a consistent temperature. I’d put frozen plastic bottles in it, which would bring the temp down but they’d often melt overnight so I’d wake up to the beer warm again. But if I only need to do this for 4 days instead of 2 weeks then I think I’ll try using it again to see if I can make it work. Thank you!
 

palmtrees

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I'd say that gives you another reason to pitch the full pack of liquid yeast or do yeast starters. A healthier pitch will give you a shorter lag time, which means active fermentation will begin more quickly and you will have less time where you need to keep the beer cool. Now that I make yeast starters and oxygenate my wort better, active fermentation will often start for me within a few hours, rather than the 12-24 hours I had seen previously. Cutting a day or a half day off of your active fermentation should make your cooling strategies all the more effective.
 

Bobby_M

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Likely your mash temp was a few degrees below the recipe's design which made a more fermentable wort. Fusel alcohols can be suppressed by a cooler fermentation temp and yes, even if you do it for the first 3-4 days of fermentation, it will help.

I would say 1 full pack of yeast from Wyeast or White Labs would be appropriate for 2.5-3 gallons of ~1.060 wort as long as that pack is 1 month old or less. 2 months is pushing it. If it's 3 months old or more, that's a significant underpitch and stressed yeast can push fusels as well.
 

charlesbrewer

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over pitch is usually least concerned. Most probably mash temp too low. Check thermometer?
 
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Joeymacca

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Thanks everyone for your responses. I’m in the middle of a renovation so won’t be able to brew until probably august. But the few things I’ve learned from everyone is:
1. Over pitching isn’t a huge concern
2. Monitor mash temp more closely
3. Ferment colder
I’ll give those tips a try next time a brew. Thank you!
 
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