[6] In 1855, his son Sir James Power, laid the foundation stone for the O'Connell Monument,[3] and in 1859 became High Sheriff of Dublin.

[3][1] During this period, when the Dublin whiskey distilleries were amongst the largest in the world, the family-run firms of John Power, along with John Jameson, William Jameson, and George Roe, (collectively known as the "Big Four") came to dominate the Irish distilling landscape, introducing several innovations.

When Alfred Barnard, the British historian visited John's Lane in the late 1880s, he noted the elegance and cleanliness of the buildings, and the modernity of the distillery, describing it as "about as complete a work as it is possible to find anywhere".

[4] At the time of his visit, the distillery was home to five pot stills, two of which with capacities of 25,000 gallons, were amongst the largest ever built.

[4] In addition, Barnard was high in his praise for Powers whiskey, noting:[4]The old make, which we drank with our luncheon, was delicious, and finer than anything we had hitherto tasted.

It was as perfect in flavour, and as pronounced in the ancient aroma of Irish Whisky so dear to the hearts of connoisseurs, as one could possibly desire, and we found a small flask of it very useful afterwards on our travels.The last member of the family to sit on the board was Sir Thomas Talbot Power,[8] who died in 1930,[10] and with him the Power's Baronetcy.

[12] However, with many of the Irish distilleries having closed in the early 20th century in part due to their failure to embrace a change in consumer preference towards blended whiskey, Powers were instrumental in convincing the remaining Irish distilleries to reconsider their stance on blended whiskey.