Yeast Day 14th April 2012 - Continued
We had a brief discussion on dried yeasts, their pros & cons and went through the tips and tricks to getting the best out of dried yeasts should you not have time to manage or prepare a liquid strain.
Why use Dried Yeast?
cheap as chips
easy to store (but you should store in a fridge at home)
easy to use
The main thing to take from this is if you do nothing else, ALWAYS re-hydrate dried yeast with boiled water with a temperature of at least 26 deg Centigrade, (its surprising how many people that go to the trouble of making an all grain beer (5-8 hours of work), then they spoil their chance of making the best beer possible, by sprinkling a pack of dried yeast on wort at 18-20 deg,). Sprinkling kills a great chunk of the dried yeast, so always re hydrate with boiled cooled (26-35 deg C) water. You will get so much better fermentation and better beer as a result.
We then went to discuss the liquid yeast strains available to everyone in the UK.
I will add here that if you want to really dial in a flavour in a beer you intend to make, a bit of online research and prudent yeast choice is going to pay dividends in your finished product. Dried Nottingham is not going to give you a decent hefeweizen, so if you want to add that extra dimension, take some time to experiment, it will pay dividends. I will also add if you learn to make slants, you will probably only ever need to buy one particular strain ever again, Liquid yeasts are not expensive if you know how to look after them.
Yeast strains are available from White Labs and Wyeast, both American brands and available in many online homebrew suppliers. But make sure you keep the vials in refrigeration, or you will be asking for trouble. Brewlab in Sunderland is also a very affordable and good source of liquid yeasts already supplied on slant and if you want to pay the earth you could also try the National Collection of Yeast Cultures
It was then time for lunch and a stretch of the legs. I had a good chat about what we had learnt and had the usual discussion on equipment etc with the other brewers (its amazing what home brewers get up to tinkering & making things in their sheds and garages, to make life easier for brewing) and I dined on a diet of Leicestershire Cobs washed down with a spectacular Galaxy light bitter, kindly given to me by Peter F. (over the years I have tried a number of hobbies including fishing, road rallying, CB radio, etc etc, however I have never ever come across a more agreeable and friendly crowd as the lesser spotted home brewer, and long may it stay that way. I have never gone to a meet and left empty handed, or not tried a new beer)
The method is to make a starter wort to a gravity of 1035 og, then add agar flakes or powder, (plenty of places sell it, but Asian shops are usually the cheapest source), pour into 30-50ml sample bottles, fill about 1/3rd full, place the sample jars in a pressure cooker and steam for between 15 and 30 minutes at full steam to sterilise the sample slants.
(note when doing this you need to a) ensure the bottles are upright in the steamer b)the bottles are made from polypropylene or glass, not plastic or they will melt in the heat c) you have cracked open the lids on the bottles, to allow gas equalization. Failure to do this will result in a few small explosions in the pressure cooker and a mess for the wife to clean up)
Once steamed tighten up the lids on the bottles so they are sealed, and place resting on an angle until they set, about 20-30mins waiting time. Once the agar/wort mixture has set you are ready to start the inoculation culturing process.
To inoculate, which is pretty straightforward, you need to flame your wire, open your yeast vial, White labs, etc, dip the sterilized wire in the yeast. Then streak the yeast on the wire over the surface of your prepared slant, ensuring you don’t leave the pots open for long in between operations, and also ensure you work close to the flame source at all times.
Once streaked you then put the slopes in a temperature stable warm environment (20 deg constant is ideal) with the lids slightly cracked to allow co2 release, for 3-4 days, (you will see the yeast culture growing on the surface of your agar slant during this time, great for keeping the kids amused). & once you have given it 3-4 days the slope can now be stored in a fridge for up to 6 months safely with no real detriment to the yeast strain. If you want to keep the strain going indefinitely, you repeat the process every 4-5 months and streak from your stored vial, onto a freshly made one, yet another hobby & I am introducing you all to “Culture” (I’ll get my coat).
By doing the above, you are able to over time, build up your own yeast bank, and if you can get your fellow home brewers interested in this practice, you will have yet another thing to swap on meet ups Win Win for everyone.
Summing up I had a great day out, I would like to thank the Midlands Craft Brewers for inviting me. I learnt a very simple but effective technique & its something I intend to do going forward. I hope my ramblings have inspired you to go and have a go yourself.
For further information on Yeast & Brewing try the following resources
Yeast Culturing FAQ by Mike Sims clear guide to making slopes
Yeast By Chris White & Jamil Zanasheif This is an invaluable book for all home brewers and it will unlock a lot of useful knowledge as well as help you understand yeast better.