mythical problems with using a bucket for secondary?

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stoutaholic

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There are two major critiques of using plastic buckets as secondary fermenters:

1. They are oxygen permeable
2. They have a large amount of headspace.

I've had a hard time verifying that #1 is actually an issue. It seems unlikely to me that the amount of oxygen that could permeate an HDPE bucket would have any significant effect on beer. I've read that more air probably gets into the beer through the rubber stopper than through the sides of the bucket. However, I can't seem to find any scientific information regarding whether there is a measurable oxidative effect of keeping beer in an HDPE bucket for an extended period of time. Does anyone know of a definitive resource that can answer this question?

As for the second critique, the headspace can be negated by sparging with CO2. I CO2 sparge my glass carboys anyway, so this disadvantage of buckets wouldn't even be an issue for me.

I have always used glass carboys for both primary and secondary fermentation, but am thinking of switching completely to HDPE buckets with a spigot installed, because:

1. They make transfers much easier (no siphoning if a spigot is installed in the bucket)
2. They allow easy removal of krausen, since the lid can be removed.
3. A bucket with a spigot would allow you to takes samples of the beer for tasting/hydrometer readings without exposing the beer to oxygen or a wine theif.
4. They are much easier to clean

And, really, if I am using a non-abrasive wash-rag to clean the buckets, I don't see how they are likely to get scratches. I HAVE scratched my glass carboys with the side of my carboy brush, though.
 
1. They are oxygen permeable - any pail sold by a homebrew company will not be permeable to any extent.
2. They have a large amount of headspace. When you rack, the headspace is filled with CO2.

Spigots are great. Just be certain they are tightened properly before adding wort/beer.
 
Personally, instead of looking at the drawbacks/benefits of using a bucket for secondary, I would decide why I am bothering to secondary at all.
 
Personally, instead of looking at the drawbacks/benefits of using a bucket for secondary, I would decide why I am bothering to secondary at all.

Well, I am considering using a bucket even for lagering, where multiple transfers are required. This is one huge advantage of having a vessel with a spigot. When doing a lager, I have to transfer to secondary, then transfer again for lagering, and then transfer again for bottling. It is a necessary part of the process for clarifying the beer. For a dark ale, I agree that even a secondary would not be necessary if you are not doing extended finishing.
 
It is a necessary part of the process for clarifying the beer.

I just don't see this as being the case. If there are yeast/trub on the bottom of a vessels there is nothing stopping further clearing. In other words, transferring to a second container is not needed for the beer to clear nor will it help it clear faster. The big push for transferring to secondary comes from the idea that you need to get the beer off the primary yeast cake fast before autolysis occurs. I have left beers (ales) at room temp for upwards of a month with no autolysis problems. Others report the same results.

I even think that one vessel will work for lagers. Pitch cold, pitch the correct amount of yeast, and let that thing sit for 4-6 weeks. No problems and the beers should be brilliantly clear. I have made lagers and followed that schedule and racked to a keg at 4 weeks. If I bottled, I would hesitate to bottle at that point.

Also, on the point of the spigots. Unless you have one of the adjustable deals like on better bottles, aren't you getting a lot of trub/yeast when using those spigots to transfer from primary? To keep it clear you would need drain the bucket every time the trub starts to reach the level of the spigot which would be tough to determine since the bucket is opaque.

Again my opinion, but anywhere you have a liquid-air interface, there is a possibility of contamination. I would not be comfortable pulling a sample from a spigot, closing it and letting it sit.

I am not try to dissuade you from using buckets, I use buckets all the time. I personally do not think racking beers 2-3 times is necessary. Now, I will admit, I do rack to a secondary if it is a big beer and needs a long (weeks to months) period of bulk aging or I do not have the keg or bottles ready.
 
1. They are oxygen permeable

FWIW, Raj Apte did various experiments using HPDE plastic buckets as aging vessels for his Flanders Red and found that they introduced too much oxygen, resulting into too much acetic character and a premature dropping of the pellicle. Acetobacter needs oxygen to metabolize alcohol into acetic acid.

Of course, we're also talking about 12 months + aging vs. a month for mid-OG ales.

http://www2.parc.com/emdl/members/apte/flemishredale.shtml

8. Oxygen. The tertiary fermentation is traditionally done in scraped oak. Scraped, old oak barrels contribute limited flavor but retains the oxygen permeability of new wood. Estimates of diffusivity of wood and some plastics follow in the table (courtesy of Flextank.com and evalca.com). Flextank is a world leader in using polyethylene for wine aging. They claim that 200L barriques admit 20cc/L.year of oxygen but that wine could use, perhaps, four times that amount of oxygen during the bulk aging without increasing volatile acidity (acetic acid). They also report that food grade PE of any density will retain its porosity in the presence of wine for many years--it resists clogging by wine components or scalping flavor from the wine.

Material

Oxygen Permeability
cc-mm/m2-day, 23C

Wood, Oak 57
High-density polyethylene HDPE 18
Polypropylene PP 20
Polycarbonate PC 36
Nylon (not oriented) 0.62
Saran 0.02
Vinyl 20
Silicone 10600
Water 34400




Micro-oxygenation v. macro-oxygenation. How equivalent are the small doses of oxygen the diffuse through the wood on a daily basis compared to a weekly or monthly ventillation of the headspace? In the wine business there seems to be preference for the former. For flemish red or lambic, I don't know. Please comment if you have tried this experiment. In the absence of a pellicle, its hard for me to see that there would be much difference. In this respect lambic aging is different from Flemish Red. Lambics casks are often so poorly stoppered that the intact pellicle on the beer in necessary to prevent over-oxidation. With good stoppering, preserving the pellicle intact may be less important. The use of plastic fermenters, while not necessary, is very economical. Many commercial sour ales are not aged in wood (including Lambics). Nobody likes to talk about this. The good news is that the standard, food-grade HDPE bucket is the second best fermenter for sour ale.

Tank Volume [L] O2 cc/L.year
Burgundy barrel 300 8.5
Rodenbach tank, wood, small 12,000 0.86
Rodenbach tank, wood, large 20,000 0.53
HDPE bucket 20 220
Homebrew barrel 40 23
Glass carboy, 30cm vinyl immersion tube 20 0.31
Glass carboy, silicone stopper 20 17
Glass carboy, wood stopper 20 0.10
 
I guess that if you are not concerned about autolysis and leave enough beer in the bottom of the fermenter when transfering to your bottling bucket so as to not disturb the yeast layer, then, yes, you would not need to transfer to secondary.

My experience has been that each transfer stirs up some amount of yeast and carries it into the next vessel. So transfering the beer, letting the yeast/trub settle out for a few weeks, and then transferring again seems to result in the final bottling being clearer, because less yeast/trub is carried over each time.

Your point about the spigot carrying a lot of yeast over does worry me though, since it is draining so close the bottom. That may very well be a problem that I have to solve.

However, assuming that I do a secondary fermentation, which many people consider standard practice, is there really any reason to be concerned about oxygen permeating the walls of the bucket and oxidizing the beer over an extended period of time?
 
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