Republished from BrewingTechniques' May/June 1996.

Fluoridation of the Brew Water Supply

A: I am surprised that California is just now, in 1996, getting around to fluoridating (or more correctly, mandating that local water companies fluoridate) the state's drinking water supplies. Fluoridation is a well-tested technique that has been proved to greatly reduce the incidence of tooth decay in children.

The standard dosage is one part per million. At this level, fluoride is tasteless and harmless to yeast. There is no reason to remove it from brewing water. If you do wish to remove it, however, you will need to use either a reverse-osmosis filter, a resin ion-exchange filter, or distillation. All these are drastic techniques and expensive to implement. All will remove not only fluoride but essentially all ions from the water. If you use one of them, you will need to reintroduce calcium and perhaps other ions into your mash water. (See reference 1 for more details on water chemistry and water treatment.) In my judgment, if fluoride is your worst water problem, you are a very lucky brewer.

Stuck Mashes

A: The first thing to try with a set mash is cutting the bed. By cutting a crosshatch pattern with a paddle or spatula, you can break up the top part of the packed grain bed, leaving only the bottom few inches to act as a filter. If the bed is packed tight, that is all the filtration you need. Be aware, though, that you cannot cut the bed all the way to the bottom; if you do, the wort will run cloudy. Also be aware that a set mash will usually try to reset itself, so cutting the bed may have to be repeated regularly during the runoff and sparge.

For a really bad case - one where cutting has little or no effect - the usual remedy is to stir the mash thoroughly to break up the entire packed-down filter bed. Add some hot water if necessary to make the mash loose enough to stir. Then let the mash sit for at least 15 minutes before starting over again with your recirculation. While you wait, try to figure out what caused the set mash. Maybe you just ran the wort out too fast. Maybe your malt is crushed too fine. Or maybe you used a problematic grain in your grist; both rolled oats (not brewer's flaked oats) and malted rye have given me trouble. In any case, your best hope for avoiding a repetition is to run the wort off slowly to avoid packing the filter bed too tight.

One equipment problem that often contributes to set mashes is having an unsuitable runoff valve on the lauter tun. Any valve can get blocked with grits and husk pieces, but some types are more prone to this malady and are harder to flush out than others. With a butterfly valve, a quick flick open then shut again is all it takes to clear the blockage. The momentary surge does not pack the grain bed appreciably. Ball valves are also easy to clear. Try one of those valve types if you have trouble getting a steady, slow runoff.

Toxin-Free Brewing Equipment

Speaking of toxicity, does mashing in a standard "non-food grade" picnic cooler at standard temperatures and pH levels cause any toxic leachings from the plastic? Also, does mashing with a standard, cheap, finished canoe paddle at standard temperatures and pH levels cause any toxic leachings from the finish on the paddle?

A: Copper has been used for centuries for brewing vessels, and if there were any hazards posed from it I'm sure Ralph Nader and his squads of neo-Prohibitionist "health experts" would have discovered them by now. I would also wonder why copper is the material of choice for domestic water lines. As a matter of fact, some breweries with all stainless steel vessels and piping have actually had to splice some copper pipe into their wort lines for proper yeast nutrition. I'm surprised to hear of a moonshiner who is down on copper. What did he build his condenser coil from?

Regarding picnic cooler mash/lauter tuns, I think I can reassure you. Some plastics do contain binders that can leach out into hot water and are toxic. I called Aladdin Corp. (their headquarters are here in Nashville), and they told me that their picnic coolers are made of polypropylene. I suspect other makes are too; picnic cooler plastic liners all appear similar. I looked up polypropylene in the plastics section of my Cole-Parmer catalog and found out it is pretty tough and inert stuff. It can take temperatures in excess of 270°F (132°C), and is rated as "excellent" (no damage with six hours exposure) to corrosive substances such as caustic soda and sulfuric acid - both at 50% concentration! Its weakest point appears to be poor resistance to volatile hydrocarbons such as gasoline. Very high concentrations (10%) of strong oxidizers like chlorine can also cause damage. Needless to say, nothing in wort or even beer is even remotely that active chemically, so I'd say it's a pretty safe material for brewing.

The Aladdin spokeswoman cautioned me, though, that picnic coolers are not insulated well enough to hold high temperatures very long. The foam insulation is not very thick, and for cooling they rely heavily on the melting of ice to maintain a steady temperature. So you might want to check your picnic cooler's heat holding abilities by doing a trial "mash" with 150°F (66°C) hot water to see how fast it loses heat.

As for canoe paddles, most are finished with a polyurethane varnish. Many pub brewers use canoe paddles to stir their mashes. I have never heard of any reports of off flavors or toxic effects caused by using these paddles. However, I have not been able to find a source of authoritative information to confirm that it is harmless when exposed to hot mashes. Perhaps one of our readers could help out here. Meanwhile, if you want to be cautious, you could sand the finish off the paddle before using it in your mash operations.

High Terminal Gravities

A: I noticed two red flags in your account of your fermentations. was that your beer took 7-14 days for primary fermentation. This is a little long. I would expect an ale of 1.060 original gravity to ferment out in 5-6 days at most. I think you will get stronger fermentations once you start using your new aerator.

The second red flag was making up a starter 5 days before brewing. You should pitch a starter at high kräusen, or when the head of foam is at its highest. For ale starters held at room temperatures and well aerated, this is normally about 24 hours after it is made up. For 10-gal batches of ale, I recommend a two-step starter procedure: first step, one cup of sterile wort; second step, one quart of sterile wort. For a two-step starter, five days for the entire procedure may be right as it can take as long as three days for the "smack pack" to swell up. But the two starter steps should take only one day each.

I worked with Wyeast #1968 a little when I was at The Saint Louis Brewery. It has wonderful flavoring properties and is as good an ale yeast as I have ever found. However, it is extremely flocculent, and this trait goes along with low attenuation. Wyeast's literature lists the apparent attenuation as 67-71%. This means the terminal gravity of a 1.060 wort could be as high as 1.020. By way of comparison, strains #1007, #1028 and #1056 all are listed as having an apparent attenuation of 73-77%, which means you could expect a 1.060 wort to ferment down to around 1.015. In practice, I have seen #1056 ferment worts in this gravity range to even a little lower.

In other words, the final gravity of your first batch was only a little higher than expected, and your second batch, where you bent over backwards to get a complete fermentation, was well within specifications. Considering these facts, I believe you have already done everything you need to do. The basic fact is that ale yeasts vary quite a bit in their ability to ferment maltotriose.

Yeasts for Unusual Beers

A: Among the many glories of the new Brewers' Market Guide (2), which is put out by the same excellent group that publishes this magazine, is the most comprehensive guide to yeast cultures that I have ever seen. In one place you can get the lowdown on just about every yeast available from any commercial lab in this country, and some from elsewhere. "The Yeast Directory" is a marvelous compilation, and I have already spent a long afternoon lost in its pages. Sigh. Makes me wish I was a home brewer again.

Back to the question. One of the problems you face in attempting to duplicate the 19th century ales is that most British breweries of that era used mixed yeast strains, in contrast to our modern practice of using pure cultures consisting of a single yeast strain. Research by the late Roger Bergen and others indicates that beers of this era that were kept for long periods often had the "horse blanket" tinge of Brettanomyces yeast in addition to the normal Saccharomyces fermentation characteristics. If you are gung-ho for authenticity, you might want to do a mixed

DE Filtration

A: My first thought is that you're taking an awful lot of trouble to make cloudy beer. For brewpub purposes, where all you care about is getting beer that looks optically bright in the glass, fussing around with different grades of DE is unnecessary. For beer destined for bottling, where your rough DE filtration will be followed by a sterile filter (sheet or cartridge), it may make sense to use different grades of DE in the precoat as you are doing in an effort to remove as much colloidal material from the beer as possible, thus minimizing the load on the final filter. But you can filter the yeast and chill haze from beer sufficiently with Celite 512 alone. I know because I have done it. Celite 512 has a nominal rating of 5 microns and is equivalent to a 50:50 blend of Standard SuperCel (about 2.5 microns) and HiFlow SuperCel (about 8 microns). Other DE makers market equivalent grades.

There are only two possible explanations for the fact that your DE filter is not clearing the beer. First, the filter bed has some sort of breach on one or more of the leaves, which is allowing the beer to flow through without being forced through the layer of DE. If the breach were a small tear in the screening material of one or more leaves, the cellulose fiber (Celite's brand is FibraCel) should bridge the gap and hold the DE cake in place, so that is probably not your problem. Another possible breach, and one that FibraCel can't do much about, is where the leaves meet the spacers that separate them. (Note: This refers to horizontal-leaf filters, which are the most popular type for small breweries.) Check to be sure that your stack of leaves has been sufficiently tightened down. Any play between the leaves must be eliminated. Be careful, however, when tightening down the nut on the top of the stack. It can be stripped, and then you're in a heap of trouble.

Another area to look at is bell pressure. In my experience, when filtering carbonated beer, the pressure in the bell (filter leaf compartment) must be at least 1.5 bar (22 psi) to hold the filter cake together. At lower pressure, the cake will be loose enough that it will not trap all the haze and yeast flowing through it. With a filter of open dosing tank design (filters with a separate pump to feed the DE slurry into the stream of beer that is going into the bell), you may have to restrict the output from the filter at the discharge valve to establish sufficient bell pressure at the beginning of the filter run. Later in the run you may be able to open the discharge valve fully, but if you do this, keep a close eye on the pressure gauge and move slowly.

A final observation on your technique: If you filter directly from a unitank into a serving tank, you will probably be better off if you do your precoat with beer instead of water. The first barrel or so of beer from a unitank cone contains a lot of yeast. It is better to use this yeasty beer to make up the precoat. If you run it in on top of a clean precoat made with water, it can blind the precoat because you can't feed DE in heavy enough to cope with it.

References

(2) Deb Jolda, "The Yeast Directory - The Compleat Guide to Commercially Available Yeast Strains," The 1996 Brewers' Market Guide (BrewingTechniques, New Wine Press Inc., Eugene, Oregon, 1996), pp. 40-59.