Oxy­genat­ing Wort, Fruit Beers, Dark Malts

Craft Beer & Brewing Magazine - - Ask The Experts -

Home­brew ex­pert Brad Smith, au­thor of the Beer­smith brewing so ware and the voice be­hind the Beer­smith pod­cast, tack­les your home­brew­ing ques­tions about oxy­genat­ing wort, brewing with fruit, and us­ing dark crys­tal and other darker malts.

Do I re­ally need to aer­ate/ oxy­genate my wort be­fore pitch­ing yeast when brewing? If so, what’s the best way to do it?

The short an­swer is “Yes, you need to aer­ate/oxy­genate your wort.”

While home­brew­ers con­sider any oxy­gen in their nished beer a bad thing, oxy­gen is crit­i­cal for proper re­pro­duc­tion of yeast cells dur­ing the “lag phase,” when they are just wak­ing up. Dur­ing this phase, the yeast cells are rapidly re­pro­duc­ing and need oxy­gen to grow. Un­for­tu­nately, the process of boil­ing your wort forces al­most all the dis­solved oxy­gen from it, leav­ing it oxy­gen-de­pleted.

So you need to add some oxy­gen back into the wort af­ter boil­ing, but be­fore pitch­ing your yeast, to get a strong fer­men­ta­tion. By far the best way to do this is by us­ing pure oxy­gen. In fact, one of my new fa­vorite toys is an “oxy­gen wand,” which is a stain­less-steel tube with a stain­less aer­a­tor at one end. You at­tach the wand to a tube and a reg­u­la­tor that

con­nects ei­ther to an oxy­gen tank or a dis­pos­able oxy­gen can­is­ter. For about ‚ƒ„, an oxy­gen wand can aer­ate your en­tire batch to the ideal …−‡„ ppm oxy­gen con­tent in about ƒ„−ˆ„ sec­onds. I use it af­ter trans­fer­ring wort to the fer­men­tor, just be­fore I pitch my yeast. It works well with cider, mead, and wine, too.

A slightly less eŠec­tive method is to use an aquar­ium air pump and aer­a­tion stone. You can Œnd these at any de­part­ment or pet store that car­ries Œsh/aquar­ium sup­plies. To use one, sim­ply san­i­tize your aer­a­tion stone and tube, put them in the wort, and start the pump. It’s best if you also have an in­line Œlter to avoid draw­ing am­bi­ent yeast/bac­te­ria in with the air. Un­for­tu­nately, since air is only ’‡ per­cent oxy­gen, you won’t be able to quite reach the ideal …−‡„ ppm oxy­gen level. It will also take some time—likely ’„−”„ min­utes.

The third op­tion is sim­ply splash­ing the wort around both as you are si­phon­ing and while in the fer­men­tor. Shake, rat­tle, and roll the fer­men­tor as much as you can to try to get oxy­gen into it. This works well

with a bucket or car­boy as long as you can tem­po­rar­ily seal it. It is not as eŠec­tive as the pre­vi­ous two meth­ods, but it is far bet­ter than do­ing noth­ing. Fruit beers are no­to­ri­ously di•cult to for­mu­late and fer­ment prop­erly. Sev­eral chal­lenges need to be over­come to get a good fruit –avor in your beer. First, you need to un­der­stand that fruits are mostly sugar and water. The sim­ple sug­ars in fruits rapidly fer­ment into al­co­hol, leav­ing you with none of the sweet­ness you might ex­pect from a straw­berry or cherry beer. An­other chal­lenge is that fruits added in the pri­mary have much of their aroma and –avor scrubbed away as CO’ bub­bles through the beer. So in ad­di­tion to los­ing the sug­ars, you also lose most of the aroma. Fer­mented fruits won’t taste the same as un­fer­mented ones. Fi­nally, both the malts and the hops we use in beer tend to mask what lit­tle fruit aroma and –avor you have left in the beer.

Some fruits sim­ply don’t fer­ment out well. Straw­ber­ries, in par­tic­u­lar, tend to fer­ment to dust (un­less you use a ton of them), leav­ing al­most no –avor in the Œnished beer. Cer­tain fruits do stand up much bet­ter—rasp­ber­ries, black­ber­ries, apri­cots, black cur­rants, ap­ples, and even cher­ries tend to come through more in the Œnished beer.

There are strate­gies you can use to counter the prob­lems above. First, you can use fruit –avor­ing syrups. These are sold in a va­ri­ety of –avors and should be added at bot­tling time, and you can even add them “to taste” to get the amount of –avor you like. The only down­side is they tend to taste like syrup or soda pop in­stead of nat­u­rally fer­mented fruit.

An­other strat­egy is to use “back­sweet­en­ing.” In this method, you fer­ment out your beer com­pletely and then add some sulŒtes and sor­bates (used in wine mak­ing), which will in­hibit fur­ther yeast growth. Add the sulŒtes Œrst, about ‡’ hours be­fore the sor­bates, and then wait a few days to let the chem­i­cals in­hibit the yeast. Af­ter the yeast has been in­hib­ited, you can add fresh fruit juice or even fruit to the beer, again “to taste” un­til you get the bal­ance of beer and fruit you want. Your beer will taste more like fresh fruit than fer­mented, which could be good or bad de­pend­ing on your goals. Please keg and don’t bot­tle your beer if you back­sweeten be­cause fer­men­ta­tion could start again, cre­at­ing bot­tle bombs.

A third strat­egy is to “go light” with your beer recipe. A light wheat-beer base, for ex­am­ple, is a good start­ing point, be­cause it has very low hops and malt –avors, which should let the fruit shine through. Adding fruit to the se­condary can also help to re­duce the loss of aro­mat­ics. Keep in mind that even with a light beer base, you need a lot of fresh fruit—gen­er­ally ’−” pounds per gal­lon (ˆ„ž g−‡.… kg per Ÿ.… l) to get a strong fruit –avor in the Œnished beer.

There is a Œnal lesser-known strat­egy that se­lect mead/brag­got mak­ers use that can also be used in beer. This strat­egy is to “go big” with your recipe! It’s high risk, but when it works, it is fan­tas­tic. The ba­sic idea here is to cre­ate a fruit/beer mix that has high enough al­co­hol con­tent that the yeast cells ac­tu­ally peter out and can’t Œnish the fer­men­ta­tion. In this case, you cre­ate a high-grav­ity base recipe and

I tried my hand at mak­ing a straw­berry beer with sev­eral pounds of straw­ber­ries in the fer­men­tor, but why was there vir­tu­ally no straw­berry avor in the

nished beer?

se­lect a yeast that has mod­er­ate tol­er­ance for al­co­hol. You want the yeast to reach its al­co­hol tol­er­ance level be­fore it can con­sume all the sugar in the fruit, leav­ing some resid­ual fruit sug­ars and –avors. The idea is to cre­ate a high-grav­ity beer, fer­ment it to close to its al­co­hol limit in the pri­mary, and then add fruit to the se­condary, and the yeast will reach its al­co­hol limit. It is “high risk” be­cause you need to care­fully man­age the yeast nu­tri­ents, al­co­hol, and ph lev­els, or you won’t get a com­plete fer­men­ta­tion, leav­ing you with some very sweet and malty tast­ing beer. This might work well for a big beer such as a rasp­berry im­pe­rial stout.

I’ve no­ticed that my beers us­ing dark crys­tal malts and pale choco­late malt have a harsh­ness to them— why is this?

In his most re­cent book, Mas­ter­ing Home­brew, Randy Mosher notes that there is a “harsh zone” run­ning from about …„L to ’„„L in color, where very few malts are pro­duced. At the bot­tom of that range you have brown malt, which runs from roughly ”„−ƒ„L, and at the other end is pale choco­late, which is roughly ’„„−’”„L. But no con­ven­tional malts are pro­duced in the mid­dle be­cause malts in this range have a very sharp, harsh, bit­ter, nasty char­ac­ter. No one would buy them. Even dark brown malt takes on many coŠee over­tones, and pale choco­late can also be sharp and harsh in large quan­ti­ties.

How­ever, when we look at dark crys­tal/ caramel malts, there are sev­eral pro­duced in this “harsh” range, in­clud­ing Crys­tal …„, Crys­tal ‡„„, Crys­tal ‡’„, and Spe­cial B. They are com­monly used by ex­tract and all-grain brewers to add some color to medium beers, of­ten with poor re­sults. Along with a bit of color come sharp, harsh, bit­ter, and burnt coŠee−like over­tones.

To counter this, you need to re­ally limit the use of malts in the ƒ„−’„„L range. In fact, you are bet­ter oŠ adding a small amount of roast or choco­late malt to get col­or­ing than adding a pound or two of Crys­tal …„ or ‡„„. I per­son­ally try to keep these malts be­low ’ per­cent each for any light- to medium-col­ored beer and be­low ” per­cent each, even in a darker beer.

This is not to say that malts in the “harsh zone” don’t have their uses. I made a porter re­cently with Ÿ.¨ per­cent Spe­cial B malt, and it added a nice raisin note to the beer with­out com­ing across too strongly. I en­joy us­ing brown malt with its slight hint of coŠee. Pale choco­late, which is sharper than reg­u­lar choco­late malt, can be nice in a com­plex porter or stout. The key is that malts near the “harsh zone” need to be used spar­ingly in a tar­geted man­ner to ac­cent their –avor and not just as a method to add color to a light beer.

If you have a ques­tion for the ex­perts or want to share your ex­per­tise, email us at info@ beerand­brew­ing.com or visit our web­site at beerand­brew­ing.com.

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