re: Homebrewing Thread: Volume II

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Key Findings


- Oxygen will inevitably be introduced to beer when dry hopping. To keep oxygen levels low try adding hops during first 3-5 days of fermentation or continually purging the headspace with CO2 while adding dry hops, especially when post-fermentation.
- Dry hopping for just 24 hours has been tested for nearly complete extraction, however the size of the batch plays a role. Homebrewers will get faster extraction than commercial breweries.
- With agitation or recirculation, extraction can peak as quickly as four hours, but may also enhance the astringency, especially when hop usage rates are high.
- Dry hopping at colder temperatures will still see extraction, likely peaking in three days.
- Hop pellets have higher extraction rates than whole leaf hops.
- As dry hop rates increase, so will the amount of more non-polar compounds like myrcene (green) and aggressive tasting polyphenols. This is particularly true with high-protein and beta-glucan grist.
- In general, hops low in a-acids will have more polyphenols than hops high in a-acids.
- Polyphenols peak after three days of dry hopping and will have higher extraction rates at warmer dry hop temperatures.
- Increased yeast pitching rates may help to remove more non-polar hop compounds and polyphenols.
- Dry hopping too much of a particular variety can alter that hop’s profile, likely going from fruity flavors to more herbal and raw flavors.
- Dry hopping in stages will result in greater extraction than one large dry hop addition.
- Both a-acids and humulinones (oxidized a-acids) will increase beer foam, but higher beer pH from dry hopping can negatively impact beer foam as well as hop varieties high in fatty acids.
- Chit malt can help increase foam stability as well as slightly increase beer clarity.

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Key Findings


- Desirable monoterpene alcohols like linaool and geraniol have been found to extract quickly during dry hopping. When agitated their extraction can take place in hours and when left static extraction was primarily done after just one day.
- Greener and resinous tasting hydrocarbons like myrcene are retained in higher concentrations in hazy IPAs and can mask some of the fruitier more polar compounds. One test found that myrcene levels raised rapidly after the first 24-hours of dry hopping leading towards a less fruit-forward beer.
- Hop thiols are important to overall flavor and aroma despite being in hops in lower concentrations because of their low taste thresholds. One commonly studied thiol called 4MMP was also found to extract quickly in beer during dry hopping, peaking after just two days.
- The longer dry hops were on a beer, the lower the head retention. In addition, alpha-acids from hops help improve beer foam when introduced at cooler temperatures.
- Too many polyphenols from dry hops can lead to astringent and bitter tasting beer. The cooler the dry hop temperature and the shorter the duration, the less polyphenol extraction will likely take place.
- Cooler and shorter dry hop durations can lead to less hop creep.
- Metals from hops can have a negative impact on beer stability and in particular manganese has been found to be one of the most efficient at extracting. Shorter durations and cooler durations were found to reduce this manganese extraction into beer, potentially helping with long-term stability.

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Not sure if i posted this in the past, but a few of us have ScottJanish's book on the New IPA,

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im about halfway through.

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there are a bunch of ideas i would like to implement into my brews regarding hop type, timing and temp. I really like the book and how he references all these studies on hops that date back hundreds of years.

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yes i split the batch into 2 different fermenters with the same dry hop schedule. And yea i thought to so but it made a noticeable difference.

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I have this Frankenstein beer that was a mess up by nothern brewer. It is a stout like beer but is very dry. Anyway to back sweeten it and give it some body? It’s finished fermenting.

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Seems like the NEEPAH just has a higher attenuation

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now i have a RIMS i can not wait to do a full stepped mash and a true mash out.

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